Monthly Archives: May 2010

What is Accuracy?

A Definition

Accuracy can be subjective.

For example, if I said that I had a pretty accurate rifle, but did not clarify that statement, one listener might think that I had a rifle that could shoot .5 MOA (1 MOA = 1.047″ at 100 yards), while another might think that I had a rifle that could shoot 2 MOA. The first guy might think that I based my statement on a single three shot group. The second might think that I fired ten shots.

Which person would be right? Well, they might both be “right.” If I had a rifle that would never put a round outside a 2 MOA circle at 100 yards, I would consider it to be “accurate”.  Another person might be totally disgusted with the concept of that rifle and would consider it to be inaccurate and wholly useless for their needs. They might settle for nothing less than .5 MOA.

That’s why we tend to define accuracy in terms of hard numbers, though wiggle room can be found there as well. How many shots make up a group? Does every round count, or can you ignore one or two outlying holes on the target?

Standards for individuals vary. I’ve heard statements such as “Five shots satisfies my definition of accuracy” and “If you’re going to shoot ten rounds, you might as well shoot a hundred”. I’ve also heard statements such as “three shot groups are worthless.” Again, who is right?

Military Standards

I turn to what professional organizations consider to be accuracy testing. When I say professional organizations, I’m talking about the military and large governmental organizations. They’re not messing around, and they have nothing to gain by allowing subpar ammunition and rifles to be purchased. Every one of these organizations bases its accuracy standards on multiple ten shot groups – normally between three and six, but sometimes as many as ten. The average of these groups is used when a weapon or ammunition is being considered for purchase. For example, here’s the most recent (as of this date) FBI 5.56mm ammunition RFP.

But why? Why do they go with ten shots, if three or five shots are “good enough” for a number of people – including, apparently, every firearms magazine writer on earth?

Well, groups don’t tend to get a whole lot bigger after ten shots. A three shot group might quadruple in size by the time it becomes a ten round group, but (barring some outside influence or weapon/ammunition failure) it would be exceptionally rare for a ten shot group to quadruple in size by the time it becomes a twenty or thirty shot group.

“So what,” you say. “If I can put three rounds in an inch at 100 yards, that makes me a marksman of the highest order, and my rifle second to none.”

Well, there’s a big problem with that, but I need to define a few terms before I go on. Point of aim (POA) and point of impact (POI) refer to where the shooter intends to place a round, and where the round hits the target, respectively.

At the Range with a Rifle that can shoot 1 MOA “All Day Long”

Let’s assume the following about a shooter and his rifle.

- The weapon is properly zeroed for the ammunition to be fired

- The target is at a known distance and the weapon is zeroed so that point of impact is the same as point of aim

- There are no outside influences such as wind to interfere with the flight of the bullet

- The shooter is well rested and the weapon is supported in the same manner as when the weapon was zeroed

Now, if that shooter claimed to have previously fired a 1 MOA group, I would assume that his claim meant that the next round out of the barrel would land within 1/2″ of his point of aim – in this case, the bullseye. And if he had just fired a 10 shot, 1 MOA group, that would most likely be right – if the round was more than 1/2″ away, it wouldn’t be very far. However, if he had just fired a 3 shot group, he might be surprised to find that that round was way more than 1/2″ away.

He could fire a few more rounds, and they might or might not be close to the bullseye. They might or might not be “sub-MOA” in relation to one another. But when one collects a number of 3 or 5 shot groups that have been fired consecutively (with no change in any factor that relates to accuracy) and overlays them, invariably, they become larger. How much larger? That depends.

There’s no real way to translate the accuracy shown by a 3 shot group to that shown by multiple 10 shot groups. There is no honest way to compare a rifle that shoots 1.5″ 10 shot groups to one that shoots .75″ 5 shot groups. Why do people insist on using three and five shot groups as standards for accuracy? Because they become frustrated with the performance of their weapon in relation to what they see or hear on the internet or in magazines, especially when they shoot ten shots. They back their groups down to three and five, throw out “fliers” and “bad groups”, and report great accuracy just so they can fit in.

What is Accuracy?

You see, an accuracy claim isn’t simply representative of past performance – it’s essentially a guarantee of future performance. One three or five shot group only tells you what your rifle did one time – a number of ten shot groups, averaged out, tells you what your rifle can do every time.

Accuracy is ATK saying to the USMC: “This ammunition will not shoot groups any larger than 2 MOA out of an M4 Carbine”. It is a rifle manufacturer saying to you, a customer: “This rifle will not shoot groups any larger than 2″ at 100 yards.” It is you saying to yourself: “I know that the next round I fire from this weapon will be within 1 MOA of where I intended it to go – no exceptions.”

So the next time you’re at the bench shooting for small groups, don’t throw anything out. Don’t ignore a few supposedly errant shots so that you can feel better about yourself or your rifle. Don’t be ashamed if you can’t match what you see in a magazine or online. Look at the big picture – overall, what was the rifle capable of? I find it ironic that some of the most inaccurate claims regarding a rifle’s performance are those relating to the mechanical accuracy of the weapon.

Much credit has to go to Molon for his tireless work towards educating the “internet public” about this topic, especially his thread on AR15.com titled “The Trouble with 3-Shot Groups“.

Why Fox News is Wrong About the M4 Carbine

Today, Fox News published this article about the M4 Carbine. It contains numerous inaccuracies which seem to be in three areas – accuracy, reliability, and terminal effectiveness. I will address each of these in turn. However, I must clarify a few things first.

The first line of the article states that the AK-47, as employed by the Taliban, is more effective for use in Afghanistan than the M4. This is so false as to be laughable. The weapons and ammunition used by the Taliban are a far worse choice for the task than the M4 and its 5.56mm ammunition. Scoring a hit on a man with a worn out AK at 600 yards is an exercise in luck, not skill. As for other issues relating to Taliban marksmanship, read this article.

Next, the “study” cited by Fox is actually the master’s thesis of Major Thomas Ehrhart, who is currently a student at the Command & General Staff College – a person with an opinion to be respected, no doubt, but this is not the same as a US Army study. The paper was titled “Increasing Small Arms Lethality in Afghanistan: Taking Back the Infantry Half-Kilometer”. For those that don’t know, a “half kilometer” is 500 meters.

It is unfair to Major Ehrhart for Fox News to take sections of his paper out of context and attempt to draw conclusions from said out of context quotes. Sadly, news organizations do this all the time. Now, that said, I do not agree with all of Major Ehrhart’s conclusions, and will explain myself accordingly.

Had the folks at Fox actually read the paper, they would have noticed where it stated that “the most immediate and cost effective improvements come from training and education. Soldiers and leaders need to understand the capabilities and limitations of their organic weapons. They need to understand what is required to maintain their weapons and keep them operational in all environments”.

Accuracy

In other words, current training does not teach the Soldiers how to wring out the most capability from their weapons – both in a reliability sense, and in an accuracy sense. While the US Marine Corps trains to shoot at targets that are 500 yards away, the US Army only trains to 300, and qualification standards are not high enough. It is important to note that, while the Army uses far more M4s, a significant number of Marine units have been equipped with the M4 (including the platoon I deployed with), and they do not complain about the limited range of the M4 to nearly the same extent.

There seems to be a belief that the shorter barrel of the M4 makes it less accurate than the longer barrel of the M16A4. This is simply not true. Both the M4 and the M16A4, and the ammunition they fire, are held to the same accuracy standards. Variances in manufacturing from rifle to rifle and cartridge to cartridge aside, a Soldier with an M4 is no more or less capable of hitting a target at 500 meters than is a Soldier with the M16A4. I have personally fired M4 carbines at 600 yards, using military ammunition and optics (or iron sights), with accuracy comparable to that of an M16A4 using the same ammunition and optics. The weapon will be capable of delivering accurate fire to the range at which the projectile starts to go from supersonic to subsonic.

Furthermore, the optic utilized on the M4 by a lot of Army units – the M68 CCO, manufactured by Aimpoint – is a fantastic sight for close quarters combat, but of very limited use past 300 meters. There is no way to accommodate for the drop of the 5.56mm round with a single red dot, as used by the M68. Also, this sight does not aid in target identification. In case you couldn’t figure it out (Fox News apparently couldn’t), people shooting at you from 600 yards away aren’t going to make themselves easy to see. The phenomenal Trijicon ACOG, used by the USMC and some Army units, aids in target identification at range, but is not really a substitute for a dedicated rifle scope for long range shooting. It is, however, far better for the task than the Aimpoint.

What I am getting at is that Soldiers, and frankly a number of Marines as well, do not have confidence in their weapons. They are not trained or even told that their weapons are accurate at such distances, so they have no reason to believe that they can accurately hit a Taliban fighter shooting at them from 600 yards away. Because they don’t think they can hit the bad guy with their rifle, they either do not engage the target at all, or they do not use the principles of marksmanship that they were trained with to do anything but lay down suppressive fire, while they wait for the guy with the radio to call in an airstrike.

Reliability

The article, and to a lesser extent, Major Ehrhart’s study, also discusses reliability. While Major Ehrhart breaks down the factors affecting reliability, the news article does not, and simply lays the blame on the “notoriously unreliable” M4. I will discuss what the thesis states are the four causes of malfunctions in the M4, in order of importance -

1. worn/unserviceable magazines

2. a lack of proper lubrication

3. worn parts, specifically the components of the bolt

4. dirty ammunition

I agree and disagree with some of the above. First and foremost, the magazine issue. The news article seems to demand a replacement for the M4, while failing to note that nearly every proposed M4 replacement uses the same exact magazine as the M4. In other words, all those worn and unserviceable magazines would still be in the supply line, and would still be in the hands of Soldiers and Marines – and they would still be the leading cause of malfunctions, with any rifle. In the case of the XM8, it failed previously for a different, but important reason – the receiver cracked when it got hot.

Second, lubrication. I believe that lubrication is very important, especially when a weapon has been fired several thousand times without cleaning. I believe that a weapon that is dirty (that is, with actual dirt, from the earth, not carbon from spent cases) can also benefit from lubrication. However, as shown by Mike Pannone, the M4 carbine can be fired without lubrication over 2400 times before it experiences any malfunctions.

Third, worn parts. As with magazines, many of the proposed M4 replacements – such as the HK416 – use the same springs as the M4 (or would use similar springs that would also wear out with use), such as extractor spring and action spring. A spotlessly clean, well lubricated rifle with quality ammunition in a quality magazine will – without exception – malfunction if the action spring and extractor spring are unserviceable. Gas rings are also important after 5,000-10,000 rounds. Unfortunately, the tracking of rounds expended is almost never performed by the average line unit that bears the brunt of combat operations, even in training, where the majority of rounds should be expended.

I was discussing this issue with Mike Pannone (the author of the above article regarding fouling), who told me about a Marine who had replaced the action and extractor springs of all the malfunctioning rifles in his unit, and was very nearly punished for it. That the weapons went from malfunctioning to not malfunctioning at all had almost no bearing on their desire to punish the Marine – he’d gone outside proper channels, and that was wrong.

Finally, “dirty ammunition” – this was more of an issue with the original propellants used by the 5.56mm cartridge in the Vietnam era. I believe that fouling (that is, without proper lubrication) is no longer an issue, that is, as long as the shooter does not expend more than five or ten times the average “combat load” –  6 or 7 magazines, or 180/210 rounds. I am unaware of any case in which a serviceman had to fire 1000-2000 rounds from his M4 and did not have a few minutes to check over his equipment.

The news article cites the battle at Wanat that, sadly, left nine American Soldiers dead. Incorrectly, however, the article states that the M4 had problems with “locking up”, and lead the reader to believe that the malfunctions led to the deaths of the Soldiers. This is false. I have read the entire rough draft of the report on the battle of Wanat, and could find three references to inoperable M4s – one undescribed malfunction, one weapon damaged beyond repair by an explosion, and one rifle that had been fired continuously for so long that the Soldier shooting it described it as “too hot to load”. Not that the weapon “locked up”, but apparently that the receivers of the weapon were so hot from continuous firing that the Soldier could not touch them. Relating to my above comment about fouling, this particular weapon was fired 360 times – twice the standard combat load – in 30 minutes, and did not malfunction during that time.

So we have one genuine malfunction – which was, by the way, reacted to by the Soldier discarding the weapon, rather than clearing it as he was trained to do – one weapon that was destroyed in an explosion along with an M14 (as would have been any other small arm) – and one case of a rifle that was used as a machine gun, and became incredibly hot as a result. Of the thousands of rounds fired during the battle, American forces only reported one actual malfunction. These issues relate more to training, discipline, and doctrine than they do to equipment.

To sum all of that up, as Major Ehrhart pretty much states in his thesis, Soldiers aren’t trained to maintain their rifles at the individual level, and if they were, reliability problems would be reduced dramatically. If company armorers were more concerned with replacing worn out parts than making sure every rifle in their armory was clean enough to eat off of, the guys using the rifles would be much better off.

Terminal Effectiveness

Finally, terminal effectiveness. This is where Major Ehrhart and I disagree on a few points. First, the news article states that the M4 won’t kill anyone past 1000 feet. This is, simply, false, and it fails to separate the rifle from one particular cartridge fired by that rifle. The thesis does discriminate on that basis, and states that “the M855 cartridge is most effective to a distance of 200 meters after which its effectiveness is limited unless hitting a vital area of the target.” This is true and false. First, the terminal effectiveness of any cartridge fired by an infantry rifle is limited unless hitting a vital area of the target. The thesis relates an anecdotal account of a Soldier who was shot with a 5.56mm round in an extremity after another Soldier had a negligent discharge with an M249 SAW – the victim had no serious injuries.

I feel that I should also relate an anecdotal account of a lack of serious injuries resulting from a negligent discharge of a machine gun by US personnel. Like the above account, this resulted in an extremity hit on an American serviceman. In this case, though, the personnel involved were Marines, and the weapon was an M240B, firing the 7.62X51mm cartridge. A Marine sergeant, walking along a road on Camp Fallujah, was struck in the left bicep by said projectile, and the wound was surprisingly small: there were entrance and exit wounds, but no damage to bone and no long-term damage to muscle. The Marine remained in Iraq and returned to duty after a few weeks. I was part of the team that treated that Marine.

The wound was, essentially, much like those described in the thesis, but it couldn’t be attributed to the much-maligned M855 cartridge. While I am not enamored with M855 and do not believe that it is the correct ammunition for our current engagements, I also do not believe that current 7.62x51mm ammunition is the quantum leap in performance that it is made out to be.

While, as Major Ehrhart states, terminal performance would be increased by a change to a 6.5mm or 6.8mm caliber, it would also be increased by utilizing the existing 77gr Mk262 cartridge, designed for long range shooting and greater terminal effectiveness, or the 62gr SOST “barrier blind” round that is not as dependent on velocity for terminal effectiveness. Simply switching to 7.62x51mm and using the current ball ammunition, as the news article seems to suggest, would not offer the improvement that they desire.

It’s important to note that millions of dollars were spent over a period of at least 10 years on “lead free” ammunition. That’s right, environmentally friendly bullets. That project was finally declared a failure. These bullets were not supposed to kill the bad guys any “deader” than M855 – because that would be in violation of international agreements.

The US currently follows the guidelines of the Hague Convention of 1899, which places restrictions on ammunition usage. It’s ridiculous to assert that the US Military cannot use expanding 5.56mm ammunition because it causes “increased wounding”, and yet allow 2000lb bombs to be dropped on Taliban fighters. I’m going to take a wild guess and say that the bomb will cause a little more “wounding” than the comparatively tiny bullet.

Conclusion

The steps that the US military could take to rectify the above issues are:

1. Train everyone who carries a rifle or carbine to effectively shoot that weapon to its maximum range. That is, the range at which the projectile is no longer stable.

2. Stamp out the “white glove clean” standard. Train Soldiers and Marines to properly maintain their weapons. Document rounds fired through weapons in the training environment. Replace parts accordingly.

3. Ensure the widespread adoption and use of effective 5.56mm ammunition.

4. Use optics suited for the task. Soldiers and Marines can’t shoot what they can’t see.

Replacing the M4 with a different rifle does nothing to correct the serious deficiencies in training and doctrine that plague the US armed forces. Problems would continue. If the above “fixes” were implemented, complaints about the M4 would be hard to find. I could suggest a few fixes for journalists covering military topics, too, but I’ve already broken 2,000 words.

Vltor Modstocks on Sale

Due to the introduction of the IMod, Bravo Company is clearing out the “old” Vltor Modstocks for $50 apiece. Considering that you normally see used versions for $75, that’s a very good deal. At this price, it’s cheaper than the Magpul MOE, but has storage for batteries and also has a QD socket for a sling swivel. They’re available in FDE and Black here.

Beyond "The Chart"

Most AR-15 enthusiasts, especially those who spend time online, are familiar with “the chart” – a document comparing M4 type carbines from various manufacturers via a number of features. These features are generally checked or unchecked, and weapons that check more boxes on “the chart” enjoy a higher reputation than those that do not. For the most part, I agree with that assessment. I would certainly rather have a “chart checker” than a weapon related to an M4 carbine in appearance only, especially considering the rapidly closing price gap between the “cheap” and the “expensive” rifles.

However, there are a number of other factors that have an effect on the reliability or “shootability” of an AR-15. I will attempt to cover a few of them today, with the possibility of more down the road. Many of the items that I compiled are things that a lot of people take for granted, or don’t think about. I’d like for people to at least think about them, even if they decide to ignore them after reading this article.

Gas Port Diameter

Gas port diameter and location is crucial to how an AR-15 operates. These items are selected based upon a number of factors, which include but are not limited to:

  • Barrel length
  • Intended ammunition
  • Intended reciprocating mass
  • Intended use
  • Environmental conditions

In other words, the AR-15 should operate as a system, not as simply an amalgamation of parts that fit together. A quality rifle will be tested and assembled with all of the above factors – and more – in mind. Some manufacturers simply guess at what conditions the rifle will see – or don’t give it any consideration at all – and put out rifles with larger than standard gas ports. As stated, this varies, but the gas port on a 14.5″ Colt M4 Carbine will generally be ~.062″. To function with a 10.3″ barrel, the armorers at NSWC Crane enlarged the gas port to .070″. Commercial manufacturers regularly put out 16″ carbine barrels with .09″ gas ports.

Gas port roughly .090″ in diameter – this is not the ideal method to determine exact gas port diameter, but it will get us close.

Such a large gas port is unnecessary and detrimental to the reliable function of the weapon and degrades its recoil characteristics. Now, before anyone says “BOY, TRY MAH .338 WIN MAG BEFORE YOU TALK ‘BOUT RECOIL!”, remember that the original purpose of the AR-15 was to put rounds on target in a combat situation. To this end, being able to get back on target quickly is very important. It’s much easier to rapidly engage a number of fleeting targets at 300 or 400 yards with a weapon that stays on target than it is with a weapon that comes off the target.

Smaller .068″ gas port on Spike’s Tactical carbine. All else being equal, this weapon is softer shooting than the above carbine with the .090″ gas port.

Regarding function, the carbine length gas system is not the optimal choice for a 16″ barrel due to dwell time – the time between when the bullet passes the gas port and when it exits the muzzle. In other words, during that time, gas is coming back through the gas tube and acting on the bolt carrier group. An “overgassed” weapon can result in an abnormally high reciprocating component velocity, which can lead to malfunctions such as “bolt over base” (to put it simply, the carrier outrunning the magazine spring’s ability to move the top round into place) and increased wear and tear on various components. Carrier velocity will generally increase if a suppressor is used. During full auto fire, this will also lead to bolt bounce, where the bolt literally bounces off the barrel extension, thereby coming out of battery and preventing the weapon from firing.

A weapon that has been “tuned” to shoot a certain type of ammunition – such as the Knight’s Armament SR-15E3 or Bravo Company 14.5″ Midlength, among others – has outstanding recoil/muzzle jump characteristics, but maintains complete reliability with almost all types of ammunition. Proper function should be established with “serious” ammunition before the weapon reaches the hands of a consumer. In the case of a home built AR-15, consideration should be given to the above factors, and any additional ones the builder wishes to include, before buying a barrel with a large gas port.

HP/MPI Test Variations

Ah, MPI (also known as MP or magnafluxing, and short for Magnetic Particle Inspection) testing. A soothing topic that everyone agrees on.

Actually, I’m lying. I’ve heard everything from “MP testing causes problems” to “Anything that is not MP tested is junk.”

The truth is somewhere in the middle. First off, MP testing is considered NDT, or nondestructive testing, and will not in and of itself cause problems. Second, there are a lot of parts that are not MP tested and which I would not consider junk. I might not choose them over a comparably priced, MP tested part, but I would not call them junk.

What is the purpose of this testing, and what parts are tested? Well, generally, the bolt and the barrel are tested. These items are generally tested with a proof load, or a single overpressure round, before they are MP tested, in order to highlight imperfections. Generally, the purpose is to find imperfections, be they cracks, voids, inclusions, or stringers. Generally…you get where I’m going with this?

Bravo Company MFG HP/MP tested bolt

There are variations in the testing, and there are variations in standards/rejection criteria. “The Chart” covers batch testing versus individual testing, but not much else. A company could theoretically say that they performed individual MP testing of bolts and barrels, but if they didn’t reject any items, the testing would be worthless. Similarly, they could throw out parts that had obvious defects such as cracks, but not parts that had other defects as mentioned above. It’d be like Nevada requiring STD tests for all the registered prostitutes, but only pulling the ones that had AIDS.

Furthermore, barrel MP testing is closely related to barrel steel – that is, MIL-11595E certification. According to Bravo Company MFG, barrels manufactured of non-certified steel can have failure rates – as per ASTM E1444 standards for MPI testing - of 30-40%. That’s unacceptably high for any profit-driven company. Therefore, many companies don’t bother with MP testing, because a third of their products would fail the test. In addition, the certified steel is only available in large quantities, necessitating a large outlay of funds, which prevents many companies from utilizing it.

Bolt failure at the cam pin hole is a more common failure with non-MPI tested bolts, because these cracks are easily detectable by proper MPI testing. This is not to say that all non-MPI tested bolts will fail – there are other factors, such as heat treatment and steel utilized – only that some companies that bypass MPI testing also bypass the quality standards required to produce good bolts in the first place.

So the next time you hear a company say that they MP test their products, ask them what their acceptance/rejection criteria is. You might be surprised at the answer.

The Action Spring

Of all the springs critical to the operation of an AR-15, the action spring (that’s “the big one that goes in the stock”, for those that don’t know) hardly ever gets any love. Apparently, most people assume that there are only two types of action springs – carbine and rifle – and that they never need to be replaced. Nothing could be further from the truth. Just as Glock and Kimber recommend regular replacement of their recoil springs/recoil spring assemblies, it is a good idea to periodically replace the action spring. Now, plenty of people will say that they have fired ten thousand rounds through their AR-15 without ever changing the action spring, and they didn’t have any problems. They are being honest.

However, in a rifle with a very high round count that has started to malfunction, replacing the action spring – as well as other springs such as the extractor spring – can breathe new life into an old rifle. Even new rifles can benefit from a quality action spring, as the consistent fore and aft movement of the reciprocating assembly is an important factor in maintaining complete reliability. Some cheaper stock kits come with action springs that are of unknown origin and rate. Given the importance of the action spring and the extractor spring to the proper operation of an AR-15, I would not go cheap on either one.

Companies such as Sprinco offer top quality action springs designed for specific applications. If you have $22 (plus shipping) to spare and have springs of unknown origin in your rifle, you would be doing yourself a favor by ordering their action and extractor spring kit. Even if you have quality parts in your rifle, it’s always good to have spares.

Bravo Company MFG vs. Spike's Tactical

I feel that a comparison such as this has been due for quite some time. Both companies have provided me with T&E rifles, and it is only fair to my readers that I give my honest impressions of each product as they relate to one another. If you don’t have a whole lot of time, there is a summary at the bottom.

The Market

There are, of course, dozens of AR-15 manufacturers, and for the most part, the majority of them turn out decent, functional rifles. By “functional” I mean that they work, not that they are “functional” for one purpose or another. There are, of course, ammunition and magazine issues, but for the moment, I’ll focus on the weapons themselves.

Unfortunately, the percentage of nonfunctional rifles put out by some manufacturers is unacceptably high. In my opinion, this is anything over 1%. Most manufacturers seem to emphasize cost over quality (despite numerous inaccurate claims to be “mil-spec”), and even if they’ve learned by trial and error how to build a decent AR, they aren’t terribly concerned when problems arise. Generally, with these types, excuses are made, blame is shifted, etc. It all boils down to “This was a cheap AR – what’d you expect?”

Ideally, the failure rate would be statistically insignificant. Rifles put out by companies with an emphasis on quality are much closer to this goal.

What do I mean by quality? Well, building to a standard, for one thing. I like it when a company lays out a plan for a weapon and then fulfills that plan. A necessary part of this is quality control. If the company double checks all the work it has done before the product leaves the door, it is less likely for an end user to have an issue with the weapon.

The process of building an AR-15 may seem simple to those who’ve assembled one from parts, but there’s a ton of knowledge that goes in to physically creating those individual parts- companies with greater knowledge of certain processes are more likely to put out good products.

Bravo Company MFG 14.5″ Midlength

To put it simply, I can’t think of a negative comment, thought, or drawback relating to Bravo Company products. I can say quite honestly that I have never heard a negative comment about the functionality or quality of BCM products from someone who had a reasonable basis for their opinion. Despite what I feel to be an ambitious and effective print ad campaign, I think BCM still has a way to go in terms of name recognition with the majority of firearm enthusiasts. This may lead to negative comments at the range from someone who knows only ABCD – Armalite, Bushmaster, Colt, and DPMS.

The same is true for Spike’s Tactical. Neither company has been around very long compared to Colt. However, I’m not really interested in having my rifles recognized at the range; I’m interested in having my rifles work when I want them to, and otherwise perform certain necessary tasks as I see fit, such as fit inside a certain area, accept certain accessories, hit targets at distance, remain light for use on backpacking trips, etc.

Spike’s Tactical Midlength LE

It would be fair to say, I think, that Spike’s Tactical has enjoyed a fair amount of success recently with the introduction of the LE line of rifles and uppers. For its part, Bravo Company uppers and rifles have also been in high demand for quite some time. This is not because either one has a cool name or a cool logo – it’s because they produce a good product that the average person could reasonably afford.

Similarities/Differences

I’ll cover some similarities as they relate to carbine upper receiver assemblies:

Both have standardized on the 5.56 NATO chamber for reliability purposes.

Both offer uppers with 1/7 twist.

Both utilize M4 feedramps for barrel extensions and receivers. These ramps are machined before heat treating and/or anodizing.

Neither offers bare chrome moly barrels – Spike’s Tactical barrels are either chrome lined or nitrided, and BCM barrels are chrome lined. Nitriding vs. chrome lining is another subject, but both are far superior to bare steel for carbine purposes.

Both offer midlength gas systems, which I prefer for all-around, hard use weapons.

Both use premium barrel steels and both offer hammer forged barrels as an option.

Both use taper pins and parkerize under the front sight base.

Both properly stake their bolt carrier keys and use strong extractor springs. Both use Carpenter 158 steel for their bolts, which are also shot peened. Both use tool steel, which offers exceptional resistance to deforming, for their extractors.

Both have shown a definite interest in gas port diameter and how it affects the functionality and recoil characteristics of the rifle. I will be discussing this more in a later article.

There are other similarities in terms of features, but I will focus on the differences in the interests of time and space.

BCM bolts and barrels are individually proof tested (this is done with a single high pressure round and is called HP testing) before being magnafluxed (also known as MP testing) for surface irregularities. Spike’s Tactical has expressed intent to move to that standard, but is, to my knowledge, currently not proof testing their bolts or barrels. They do individually magnaflux bolts and barrels, however, many knowledgeable individuals have questioned the effectiveness of magnetic particle testing without prior high pressure testing. Edit: I have been informed by a reliable source that all Spike’s Tactical barrels and bolts leaving the shop will be HP/MP tested within three weeks. Testing is to be performed by independent (that is to say, outside) organizations.

BCM offers optional IonBonded bolt carrier groups, and Spike’s offers optional FailZero/nickel boron plated bolt carrier groups. Relating to lower receivers, both use top quality lower parts, with Spike’s offering nickel boron plated fire control groups. I do not know the specifics of the Spike’s Tactical receiver extension tube beyond the fact that it is mil-spec in diameter (I intend to find out and report back), but I do know that the BCM receiver extension tube is of the highest quality in terms of materials and method of fabrication.

It is, of course, hard for me to verify certain things without the assistance of an advanced testing laboratory or evidence of chain of custody for individual parts. So far, I have not been misled  by either company, so if they say that they do something a certain way, I will accept that as truthful information until I am shown otherwise. There are also probably other differences that I have not been made aware of, or have not asked about. For example, I do not know what number on the Rockwell scale the barrel extensions have been surface hardened to, for either company.

Business Practices/Operations

There are other differences in the way the companies operate – for example, Spike’s Tactical seems to offer more in the way of factory customization and also offers AWB compliant weapons for those living in states that still have AWB provisions. BCM offers an exceptional variety of upper configurations, including many that Spike’s Tactical currently does not offer – such as the splendid 14.5″ midlength. However, BCM does not assemble, for example, folding front sight/gas blocks on BCM branded uppers, or fixed stocks on complete lower receivers for AWB states.

If you’re like me and place function over form, you won’t really care about minor cosmetic details. Krylon will fill in a lot of scratches. However, if you value aesthetics, you might prefer Spike’s Tactical. BCM has not expressed an interest in cosmetic appearance such as matching the anodizing of uppers and lowers, while Spike’s Tactical has at least expressed interest – second to the overall quality of the part in question. I should note that if you are unhappy with the appearance of a BCM product, you will not be denied a return for that reason. I will say that some find appearance to be an indication of quality. I have been guilty of this in the past.

One additional factor is the logo – not important to me, but some are apparently turned off by the spider logo utilized by Spike’s Tactical. I find this to be a very odd reason to not purchase a weapon, but to each their own. I don’t like spiders, but I don’t mind the logo.

Contacting BCM by phone is difficult due to the volume of business they’ve been doing since the election, though you’ll normally receive an email response to a question in a few minutes (during business hours), and you can always place an order online. Contacting Spike’s Tactical by phone is fairly easy (during business hours), so if you like talking to someone when you order a part or have a query, you might feel more comfortable with the latter company. Should you have a technical issue or problem with one of their products, both companies will do whatever they can to fix the problem in a very rapid manner.

A complete Spike’s Tactical midlength upper is approximately $115 cheaper, given the current coupon code, than a complete BCM midlength upper – excluding the buffer included with the ST product. This may will not change when HP/MP testing procedures are implemented by Spike’s Tactical, and/or when the coupon code is no longer valid. I like to tell people that the importance of a rifle’s price will not seem nearly as relevant a year or two down the road, when far more money has been spent on ammunition.

Summary

BCM has undoubtedly established itself as one of the highest quality manufacturers of AR-15 rifles for hard use. I am unaware of any fact-based reason to think otherwise. BCM products are more expensive than Spike’s Tactical products, but still represent a tremendous value compared to, say, a complete Colt carbine.

Spike’s Tactical offers a very high quality product at a price normally reserved for much lower quality products. I don’t know how they’re doing it – and yes, I’ve asked. They’re working very hard to establish themselves as a quality brand, and they’re doing a good job of it.

At the current time, I would recommend BCM for those who place quality above all other factors, or are seeking a specific configuration, and Spike’s for those who are limited by budget, but still want a high quality weapon. This is not to say that Spike’s Tactical does not put out a high quality product; only that they have not yet implemented all the testing procedures utilized by BCM, and that certain buyers might find this to be a deal breaker.

I have personally owned a considerable number of each company’s products, and have fired plenty of ammunition through said products. I have had exactly one malfunction with each, and those malfunctions can be attributed to other factors – a faulty Cammenga magazine with the Spike’s Tactical CHF upper, and faulty ammunition with a BCM midlength that I used to own. Neither malfunction would cause me to question the reliability of the weapon. Both involved external factors that I would introduce on the square range only – substandard magazines and ammunition.

BCM 14.5″ Midlength with Spike’s Tactical M4 LE

Does Nickel Boron Reduce Heat?

We’ve been bombarded with a variety of coatings and platings over the past few years, most of which are called “proprietary” and given a cool name. In reality, there aren’t a whole lot of finishes or metal treatments out there. Many are just variations on a theme, such as all the derivatives of nitrocarburization and nickel plating.

Nickel boron is related to electroless nickel plating and electroless nickel with teflon (also known as Robar’s NP3) with regard to the plating process. Nickel boron is reported to provide “permanent dry lubricity”. In other words, less friction amongst the reciprocating parts, as well as where they interface with static components.

It didn’t really occur to me that this might lead to lower operating temperatures. In fact, when I noticed a discrepancy between a rifle with a nickel boron BCG and a similar rifle with a standard, phosphate finished BCG, I wasn’t sure what to think. They used different rail systems and gas system lengths. Initially, I chalked it up to those minor differences. Then, I decided to use a standard BCG in the rifle that was originally equipped with the NiB BCG, using the same test protocol. After that, I repeated the test, twice, with each BCG, allowing the weapon to cool to ambient temperature between strings of fire.

The test was performed by firing 80 rounds of centerfire ammunition as quickly as possible through the AR-15 pictured below:

No malfunctions were experienced during any of the 5 strings of fire.

I then measured the temperature of the gas block, chamber, bolt face, and handguard (in four locations) immediately after firing and at two minute intervals out to 10 minutes.

For the sake of comparison, I have included the temperature of an M4 type carbine equipped with a KAC M4 RAS handguard. The rifle above was equipped with a Daniel Defense OmegaX 9.0. None of the rails had any covers during the testing.

Gas block temperature profiles were nearly identical for all weapons.

The same goes for chamber temperatures.

Bolt face temperatures, however, were another story.

The bolt face of the nickel boron plated BCG stayed, at its peak, 13 degrees cooler than the same weapon with the standard BCG, and 17 degrees cooler than the M4 carbine with the KAC M4 RAS.

Here is the nickel boron BCG compared with the POF RDIK and POF P-415 uppers, which underwent the same test (again, we’re talking bolt face temp here):

As always, I’m not a scientist and this was not a scientific test, but I do feel fairly confident in the results, given that I double and triple-checked the numbers and nothing was outside of a small margin of error. The above numbers are the average of said tests and retests.

I do realize that this was a sample size of one and that the limited testing doesn’t definitively prove anything. I do think that it is an interesting result that I would like to follow up on after I get more ammo and possibly more nickel boron plated BCGs.

Fake Tourniquets

Because I’m seething with rage at the moment, I won’t write very much, other than that fake tourniquets, manufactured in China, are apparently finding their way into the hands of American servicemen overseas. These fake tourniquets cannot be used to control bleeding and have reportedly contributed to at least one fatality. They are intended to be indistinguishable (to the casual observer) from real CAT tourniquets currently in use. A PDF file of the differences between the two tourniquets can be found here. Please forward it to anyone you know who is in the military, especially those deployed overseas.

We can thank the airsoft community for this fake product that can cause very real harm.

Heat Dissipation: Insulate or Circulate? Gas Tube or Op-Rod?

Standard disclaimer: I’m not a scientist and this was not a scientific test. Any conjecture on my part is purely an uneducated guess.

As I’ve written before, POF-USA provided me with two of their upper receivers – one is of their standard P-415 design and the other is actually operated via a standard gas tube. It’s called the RDIK.

This gave me the opportunity to compare how each handled heat. That is, just how effective are all the design changes POF has made to the AR receiver, barrel nut, and handguard? Well, as I found out, they’re quite effective. However, that test was pretty limited – only 30 rounds per weapon – and I wanted to step it up a little.

Today I put 80 rounds through each of three ARs – the P-415, the POF RDIK, and an M4 type AR with double heat shield handguards – and will shoot more in the next few days with other weapons. I also took chamber and bolt face temperature readings, in addition to the handguard temp (average of 4 places on the handguards) and gas block/barrel temp.

The rounds were fired as quickly as possible, and the rifles were left with the bolt carrier group in the forward and locked position. Temperature readings were taken immediately after firing and at two minute intervals thereafter, out to 12 minutes post fire.

We’ll start with handguard temperature.

As you can see, the M4′s double heat shield handguards were much hotter than either POF offering. The POF RDIK, in fact, had a slightly cooler handguard than the POF P-415.

This was in part due to the very hot gas block of the P-415. Here are those temperatures:

It wasn’t quite as scorching as the M4′s 353 degrees immediately after shooting, but it was over 320. The POF RDIK was drastically cooler – it never exceeded 200 degrees.

Chamber temperatures were much closer for all weapons.

The P-415 did stay cooler than the RDIK, with a difference of  roughly 10 degrees. The M4 was hotter than either of the POF weapons, due in no small part to the heat sink barrel nut used on the POF rifles.

The following graph shows bolt face temperature.

It would appear that a large portion of the heat reaching the standard AR-15′s bolt comes from the front – that is, the chamber. If we compare chamber and bolt temperatures, the RDIK and M4 hardly ever had more than a 2 degree difference between the chamber and the bolt (with the bolt normally being 1-2 degrees cooler than the chamber). The P-415 bolt, on the other hand, generally stayed about 10 degrees cooler than the chamber.

What does this all mean? Well, to me, it means that getting the heat out (circulating air) is more important than trying to keep the handguards cooler (insulating the barrel with double heat shields) – regardless of the operating system you choose. It would appear that the piston/op-rod P-415 does slightly reduce bolt face temperature – but the RDIK does a very fine job of keeping the chamber area cool in its own right, which in turn keeps the bolt cooler.

It seems that there is no free lunch, and the heat which is not present in the P-415 chamber and bolt is very present at the gas block. The heat sink features and wide open handguard with lots of cooling slots almost seem necessary to keep the barrel/gas block temperature relatively in line with that of the M4 type AR. I would really like to test an op-rod conversion that does not have the heat sink barrel nut, big handguard, etc.

I would assume, based on these graphs and the comparison of the three uppers, that the large majority of the temperature of an AR-15 bolt during sustained fire can be attributed to the “fire in the barrel”, and a minority comes from the gas which circulates through the action. In other words, with the piston/op-rod system, the chamber “heats” the bolt, whereas in the standard operating system, the bolt is heated not only by the chamber but in a small way by the gas coming through the gas key, which in turn causes the bolt to pass some heat back to the chamber. As a result, the temperature of the bolt and chamber on a standard AR are married to one another to a greater degree (ha, ha) than on the P-415.

Again, I’m not a scientist. If anyone has a better conclusion based on the above data, I’m all ears.

Spike's Tactical Midlength LE Upper Receiver Assembly

Some people are in the market for a new AR or AR upper.

Some people don’t think they’re in the market until something special catches their eye.

This could be a part that has special features, or a good product at a good price.

Or, for that matter, something that has special features and is at a good price.

The Spike’s Tactical LE uppers are certainly in this last category. They’re under $500, shipped, with a $50 coupon code – M4LEUP for the M4 type upper ($475 with the code), or MIDLEUP for the midlength upper ($485 with the code).

There are budget uppers available in the $300 range, but they lack many of the components – and nearly all of the features – of the Spike’s uppers.

For example, a $275-300 upper without a bolt carrier group, charging handle, or possibly handguards suddenly becomes a ~$450-475 upper. How much was the Spike’s M4 LE upper again? Oh, right. $475.

Thus, it is with bewilderment that I observe people who buy said cheap uppers. When reports of mismatched receivers and barrel extensions, missing gas ports, barrel extensions coming loose, etc surface, I am not very surprised.

Perhaps it’s inappropriate for me to divulge information that was learned in a private conversation, but I don’t think Tom Miller, CEO of Spike’s Tactical, would mind very much. 6 or 8 months ago, we were emailing back and forth about new products. When the subject of a company “goal” or “mission” came up, Mr. Miller essentially said that he wanted Spike’s Tactical to be regarded as one of the best AR-15 manufacturers in the business. That’s a lofty goal, but it’s one that they’re well on their way to achieving, if the uppers I’ve seen are any indication.

Keep in mind, there was no price “string” attached to that goal. He didn’t say “we want to be the best budget manufacturer in the business” or “we want people to say we’re the best because we’re cheap”.

I learned everything I needed to know about Tom and Spike’s Tactical from that one statement.

So, after that long-winded diatribe, back to the subject at hand: the ST Midlength LE upper assembly.

This particular upper came with a few extras, as you can see. Excellent extras, I should add – a Smith Vortex flash suppressor, a Daniel Defense OmegaX 9.0 rail, a Daniel Defense A1.5 fixed rear sight, and a Bravo Company MFG Gunfighter Mod 4 charging handle, among others.

All Spike’s uppers are marked with their logo. They might be able to assemble an upper sans logos for those who prefer a blank slate – don’t quote me on that. Here you can also see the DD rear sight and the excellent BCM charging handle. Now that I think about it, the DD rear sight is excellent, too. It’s so light that it actually reduces the weight of your rifle when you attach it…

Another nice option for ST uppers is the Nickel Boron bolt carrier group. Nickel Boron provides corrosion resistance as well as a good amount of inherent lubricity. The Spike’s Tactical nickel boron BCGs are done by FailZero, but with a little more attention to detail (such as carrier key staking and extractor/bolt quality).

Also, they offer laser engraved ejection port covers. I think they should offer one with the spider logo that also says “Surprise, Small Insects!” Sadly, they do not. By the way, the American flag is not backwards – the field (portion with the stars) is always oriented towards battle. Were the flag to be displayed in the traditional manner on the right side of the weapon, it would be “retreating.”

Evidence of test firing is plainly seen on the brass deflector. This is definitely a good thing.

An F height FSB. Taper pins that are properly driven in. These are items that some other manufacturers in the price range ignore.

M4 feedramps on both the barrel extension and the upper receiver are standard on all Spike’s uppers. This set isn’t an absolutely perfect match, but I do not foresee any issues from this particular combination.

The entire BCG – except for the firing pin retaining pin and extractor pin – are Nickel Boron plated. Because electroless nickel plating is strongly influenced by surface preparation, and because this BCG is incredibly smooth to the touch, I’m inclined to believe that every surface was polished prior to plating. Either that, or Nickel Boron has, literally, magic properties. Either way, friction should be greatly reduced.

As expected, the bolt also showed evidence of test firing. One benefit of nickel boron is that cleaning is much easier. Everything you see here wiped off with hardly any effort.

The extractor spring used is an “extra power” spring, and is identified as such by the black insert, and the o-ring provides additional extraction force. For some applications, this may be unnecessary. Still, it’s nice to have it included.

This concludes my brief overview of the basic features. More to follow…soon.

5/6/10:

I didn’t shoot any groups today, but I was pleasantly surprised to find that the iron sights had already been zeroed, and the rounds were going where I intended them to go.

The Nickel Boron trigger, hammer, and disconnector also added up to a very manageable and clean trigger pull. I will definitely be purchasing several of the Spike’s LPKs to replace standard GI triggers in a few of my lowers, including my other Spike’s lower.

And, finally, after shooting several ARs that are not so equipped, using the BCM Gunfighter charging handle was akin to returning from a long days’ work to find a home cooked meal on the table.* It’s just that good.

*In deference to all the empowered women out there, we are going to assume that said home cooked meal simply appeared on the table, as if by magic.