Monthly Archives: June 2010

AR-15 Weight Calculator

One common topic of discussion relating to AR-15s is weight.

Frequently, someone will want to know what a certain accessory will weigh, or how much difference there is between a heavy barrel and a light barrel, and so on.

I have created a very simple calculator – with links to resources from other websites – that will assist those who are looking for the total weight of their weapon. I cannot guarantee that it will be perfectly accurate, given variables relating to manufacturing processes and scale calibration, but it should provide a fairly accurate weight assessment.

It is a work in progress, so please excuse the rather boring appearance for now. More data will be added to the vuurwapenblog.com “Stock and Optic Weights” page soon.

I would like to thank 03designgroup.com (USMC03) and tacticalyellowvisor.net (rob_s) for allowing me to reference the data they have painstakingly compiled over the past few years.

McDonald v. Chicago

The bottom line: In a 5-4 decision, the Supreme Court incorporated the Second Amendment – in other words, found that it applies to state and local governments as well as the federal government.

The full decision can be read here.

My favorite quotes from Justice Stevens’ dissenting opinion, followed by my translation:

“…a rule limiting the federal constitutional right to keep and bear arms to the home would be less intrusive on state prerogatives and easier to administer.”

Translation: It’s too difficult to protect this right. Additionally, the Framers got it wrong when they made the Second Amendment so broad.

Never mind the fact that the First Amendment states in part “Congress shall make no law…abridging the freedom of speech…”, and yet, it has been discussed by the courts for generations and will continue to be discussed as long as the Republic is alive. If only Justice Stevens could stand in front of the Constitutional Convention and explain that defending liberty was just too difficult and confusing.

“Your interest in keeping and bearing a certain firearm may diminish my interest in being and feeling safe from armed violence.”

Translation: Although the Chicago handgun ban has completely failed to prevent handgun violence, it still makes sense in the recesses of my mind.

This is the essence of the dissent: ignoring logic and historical precedent, we personally feel that you should not have this right. Stevens’ first-person description is, in my opinion, telling.

“…although it may be true that Americans’ interest in firearm possession and state-law recognition of that interest are “deeply rooted” in some important senses… it is equally true that the States have a long and unbroken history of regulating firearms.”

Translation: The Court has allowed this injustice to stand for so long that we must simply continue to allow it to stand.

Sounds like squatters’ rights to me. States have squatted atop the Second Amendment long enough that it doesn’t belong to the people any more.

From Justice Breyer’s dissenting opinion:

“In my view, (the historical record) is insufficient to say that the right to bear arms for private self-defense, as explicated by Heller, is fundamental in the sense relevant to the incorporation inquiry.”

Translation: Citizens do not have the right to defend themselves in their homes with firearms if their state or local government says they don’t have that right.

I don’t think I need to expand on that point.

“There is… every reason to believe that the fundamental concern of the Reconstruction Congress was the eradication of discrimination, not the provision of a new substantive right to bear arms free from reasonable state police power regulation.”

Translation: As long as everyone’s rights are deprived equally, there’s nothing to see here. Move along, subject.

This (and similar opinions) ignores the historical precedent of gun control legislation being enacted to deprive minorities of the right to keep and bear arms.

“…our society has historically made mistakes—for example, when considering certain 18th- and 19th-century property rights to be fundamental.”

Translation: That private firearm ownership is allowed under current property law is just as bad as when slavery was legal – when one human being had the right to “own” another human being.

“…the Amendment’s militia-related purpose is primarily to protect States from federal regulation…”

No translation is really needed here, though I suppose Justice Breyer is eagerly awaiting a court challenge to the 1916 National Defense Act, which allowed the President to “federalize” the state militias (National Guard).

Perhaps Arizona Governor Jan Brewer could activate the Arizona National Guard to conduct armed patrols on the US/Mexico border in Arizona, with orders to locate, close with, and destroy armed drug smugglers entering the United States, and provide humanitarian aid to illegal immigrants while detaining them for the Border Patrol. Naturally, President Obama would federalize the National Guard troops and order them to conduct useless unarmed patrols. Governer Brewer could then claim that the state’s Second Amendment rights had been violated by the National Defense Act, and Justice Breyer would write the majority opinion which would return control of the state militias to their respective governors. Actually, that probably wouldn’t happen.

“Moreover, the Civil War Amendments, the electoral process, the courts, and numerous other institutions today help to safeguard the States and the people from any serious threat of federal tyranny.”

Translation: Subject, the federal government is here to provide a safe and secure environment for you. You don’t need a weapon to protect yourself against criminals or a tyrannical government!

That’s pretty much what Pol Pot’s troops told the Cambodian people during their disarmament, which preceded genocide. It’s happened elsewhere, too.

I’ll be updating the blog throughout the day as I read more of the opinion(s) of the Court. Make no mistake, all of this adds up to one thing: “reasonable restrictions” aren’t the goal of anti-gunners. Only the complete disarmament of law-abiding citizens will satisfy them. These comments expose their extreme goals.

Understanding Extractor Lift in the M16 FOW

For most people, the following test will be as interesting for the methods used as it is for the conclusions that were reached.

Understanding Extractor Lift

Alternate link to presentation

This presentation was initially shown in May of 2003; the “other comments” page would seem to be especially prescient in light of all the “improvements” that have been made to the AR platform in the years since. Some I fully support, such as midlength gas systems (especially for 16″ barrels), while others (such as poorly engineered “piston conversions”) I do not.

The following sentence is also quite interesting:

“Case extraction and ejection successfully occur as long as the case is held against the bolt face by the residual chamber pressure while the extractor lifts and returns to position.”

Although it is easy to put together an AR-15 from an amalgamation of random components, it seems lost on many that the AR-15 is a system that must work in harmony. The AR-15 is more than the sum of its parts. Many commercial manufacturers have taken it upon themselves to “improve” the system in order to make it work with cheap ammo, or be cheaper to manufacture, or simply because they do not understand why something was done a certain way. Such actions can reduce the service life of the weapon and compromise reliability.

Info on 5.56mm Effectiveness from Sweden

Here’s a great PowerPoint presentation on how effective 5.56mm ammunition is from a military standpoint.

I say it’s great because I agree with a lot of what it has to say, but it really does have some good info, whether you are a proponent of 5.56 or not.

I’ll let the presentation do the talking.

“Is there a problem with the lethality of the 5.56mm NATO caliber?”

One of the most interesting parts of the file is page 21, which lists muzzle velocities at various barrel lengths, from 8.3″ to 20″.

Don't Bring Your Ammunitions to Mexico

Feel free, however, to stand a few feet away from the border with them.

The enormity of the vital task entrusted to (perhaps foisted upon would be more descriptive) an inadequate number of Border Patrol agents is not truly apparent until you’re standing on the border. I thanked all of the agents I encountered today. Without exception, every agent was very polite and professional.

The “big fence” becomes a series of welded-together “vehicle barriers”, which gives way to a simple barbed wire fence a few miles later. This is what separates the United States from Mexico. This photo was taken at the border, looking towards the east, from 31.450788,-111.44285 (Lat/long provided for easy Google Maps reference).

ToolsAviation/PowerPax Battery Caddies

I’ve come across a number of items that never really appealed to me – such as this “Battery Caddy” - before I actually used them. When I received two examples as a gift (during the AR15.com Christmas Exchange), I thought, “What are these for? Holding batteries? What’s wrong with just having them in a box?” Then, as I said, I started using them, and found them to be very practical devices.

They’re injection molded polymer, and the 4xCR123 and 4xAA examples that I own weigh less than an ounce “unloaded”. As you can see, they’ll hold a variety of standard and rechargeable batteries – above, from left to right, Surefire CR123, TrustFire 16340, Tenergy RCR123A, and Tenergy CR123s fit just fine. Batteries are easy to remove with just a firm push of a thumb or finger, but I’ve never had one fall out or even partially slide out inadvertently. I’ve found them to be an excellent alternative to other battery holders, which are often flimsy and have lids that aren’t very secure – while I haven’t intentionally abused one, I’ve accidentally dropped both examples on hard surfaces without any negative effects to speak of.

The battery terminals are protected, even if you don’t slide them in the “right” way. As you can see, they’re available in a tan color, as well as OD green, red, yellow, orange, black, clear, and “Moonshine” – glow in the dark.

$4.95 seemed a little pricey to me at first, but it’s pretty reasonable for what you get, now that I’ve used them for a while. It’s nice to just grab a “pack” or two for a long trip, rather than having half a dozen batteries rolling around inside a suitcase or backpack.

Bravo Company BCM4 Lower Receiver Assembly

I used to think that all lowers were alike, and that the only real difference in lower parts kits was that some came with fancy triggers.

I now know this to be false.

After having to perform final – perhaps corrective is a better term – machine work on several “budget” lowers, I started to set my sights higher. It’s easy to cut what would seem to be fat out of an AR-15 build budget by using a cheap lower and a cheap LPK. For many (low-volume) shooters, this is just fine. For those who want – or need – something better, and aren’t willing to depend on luck to guide them to a serviceable lower and a durable LPK, there are better options out there.

One of those options is the Bravo Company BCM4 lower. It’s only available in assembled form, and comes with excellent small parts. It sells for $360, but it’s worth every penny.

I’ll start at the back.

The stock body is made of the exact same materials, and has the same exact dimensions, as the buttstock on the Colt M4. The BCM stock even uses properly heat treated latch hardware. Want to change the factory stock anyway? Cool.

The receiver extension tube is made to the “mil-spec” diameter of 1.146″, enabling the owner to install the widest variety of aftermarket stocks, and ensuring the best thread engagement between the tube and the receiver. This isn’t the only feature – it’s also made from 7075-T6 aluminum, in exactly the manner prescribed by the government for military M4s, all the way down to anodizing and dry film lube on the inside. The one deviation is that it has six positions and thus offers a greater stock adjustment range.

The “castle nut” which keeps the stock in place is staked – in two locations – having had an unstaked castle nut come loose (which resulted in a nonfunctional weapon), this makes me feel warm inside.

The BCM lower comes with an H buffer – containing the proper tungsten weight inside – backed up by a quality action spring. The action spring is one of the most important – and most overlooked – parts of an AR-15.

Grease is applied to fire control group contact points, which helps wear the parts in.

The hammer isn’t notched, which aids in reliability with 9mm uppers and unshrouded firing pin carriers. The notched hammer will stop the weapon from firing more than one round with each pull of the trigger should the disconnector fail. In fact, it’ll stop the weapon from functioning at all after that happens.

“But,” you say, “I’m worried about having the weapon malfunction like that! Isn’t that an important safety feature?”

Well, if you’re concerned about the weapon malfunctioning in that manner, you should buy a lower that has its fire control parts made to the proper dimensions, made of quality materials, and properly case hardened. The BCM lower falls into this category. In my opinion, actively trying to prevent failure is better than trying to jerry-rig a suspect method of stopping the failure after it’s already happened.

A nice touch found on BCM lowers is the inclusion of an “enhanced” trigger guard that has been modified in order to allow a gloved finger to fit. When I shoot a lot, I wear nomex flight gloves that don’t take up a whole lot of room, but this is a nifty feature for those in the frozen north.

One final note: the BCM lower is now available with an A2 stock, and I would assume that it will be available with the Vltor A5 stock assembly shortly.

So, is the BCM4 lower right for you? Only you can make that decision. If the $360 price tag completely kills your budget, then you might have to look elsewhere. However, just as a strong foundation will ensure that a house stands for a long time, starting with quality, durable parts will ensure the long service life of a carbine. The BCM4 is about as “strong a foundation” as you can get. Now that you know what you’ll receive should you choose to plunk down 360 hard-earned dollars for one, you can make an educated decision about what’s best for your needs.

Bravo Company MFG 16" Lightweight Midlength Upper Assembly

With the recent production of more Bravo Company lower receivers, complete BCM rifles and carbines will now be available. Among them is one of my favorite AR-15 configurations – the 16″ lightweight midlength.

The one you see here represents what will go on sale, with a few exceptions – the Magpul MOE midlength handguards aren’t out yet, and the production lightweight midlengths will have a .625 FSB instead of the .750 FSB on this weapon. Also, you’ll have to order the Vltor Modstock separately (and the ammunition/magazine too).

Weighing just about 6 pounds unloaded with the standard M4 stock, or 6.3lbs with the pictured Vltor Modstock, the weapon’s center of gravity is right around the front of the magwell – just where I like it. Unlike weapons with 4 more ounces of slightly heavier barrel out front, I didn’t feel the need to put the heavier Vltor EMod stock at the rear – saving me about 10 ounces overall.

Thus, I was able to add a Trijicon ACOG, model TA33, in a LaRue Tactical LT-105 QD mount and keep the weight roughly the same as a “regular” midlength with the same balance point and iron sights. That’s a big plus, and there’s no cost difference between the regular and lightweight midlengths.

Now, on to the features of this upper. Starting from the front -

Most Bravo uppers come with an A2 flash hider (or compensator, depending on the time of day and what you feel like calling it), and this one was perfectly timed. The barrel is MIL-11595E certified steel, 1/7 twist, chrome lined, with a 5.56 chamber and M4 feedramps. Every BCM barrel is individually high pressure tested and then magnetic particle tested.

All Bravo uppers that have fixed FSBs use the F-height version, as you can see in the photo.

Now, I mentioned the .750″ gas block shelf earlier. I think Bravo made the right decision by initially going with .750″ instead of .625″ – although the latter may be more “correct” for a lightweight profile, the .750″ shelf is much easier to find gas blocks for, and as you can see, a side sling swivel will fit properly on a .750″ gas block shelf. According to Paul at Bravo Company, the weight difference between the two is negligible (0.5oz) – while the .625 barrel is smaller in diameter, the corresponding FSB or gas block is generally a little heavier. As for looks, with the sling swivel on there, I can’t really tell which one it has, and even if I could, it wouldn’t really matter to me. While it’s good that BCM listens to what its customers want, in my opinion, this was a pretty silly “want.”

Moving a little farther back, this upper came ready for standard handguards, though as mentioned, future BCM midlength uppers will ship with the Magpul MOE midlength handguards. You could also install the Daniel Defense Omega rail in a matter of minutes, or any other drop-in type rail system, should you need one. You could also order the upper with a variety of free float rails installed by Bravo Company.

Here are the aforementioned M4 feed ramps. The receiver and barrel extension line up perfectly.

Another key feature, of course, is the bolt carrier group. The term “mil-spec” may be overused at times, but this is a fully mil-spec BCG that could be accepted under contract to the US Military. The shrouded firing pin M16 carrier is machined from 8620 steel, the gas key is attached with Grade 8 hardware and properly staked, and both the key and the portion of the carrier where the shot-peened bolt resides are chrome lined. There’s a chrome firing pin and a bolt made of Carpenter 158, with a tool steel extractor, an extra power extractor spring, and quality gas rings. Everything is properly heat treated. The bolt is high pressure tested by Bravo and then magnetic particle tested by a third party. There’s a lot that goes in to a quality BCG, and many think that a run of the mill BCG can be brought up to world-class standards simply by staking the carrier key on their own time and dime. That’s just not true.

The inside of the upper receiver gets special treatment, too – a baked on dry film lube. It’s a good thing to have, and it’s often overlooked.

Another thing that many people don’t think about is the Picatinny rail on top of the upper. Due to the design of modern optic mounts, this isn’t usually something that even crosses the mind of the average AR owner. However, some legacy mounts only fit rails that match the original Picatinny design exactly, allowing for no out-of-spec dimensions; every BCM upper I’ve ever owned was in spec, and this one was no exception.

By the way, the receivers are hard anodized, with an emphasis on durability over attractiveness – though as you can see, these receivers (both Bravo Company) went together beautifully.

The upper came with a few upgrades – BCM marked Troy rear sight, and the excellent BCM Gunfighter charging handle. Check out the “My Guarantee” link at the top of this page for more info about how much I like the BCM GFH.

Of course, I made it to the range as soon as possible after receiving the upper. I’ve only fired it at a 50 yard zero range and a 200m-500m steel plate range, so I can’t offer any 100 yard group sizes yet – but using the 3x ACOG, in a 10-15mph wind, I was able to engage every target on the range, including the 12″x19″ miniature ram silhouettes and the 18″ gong at 500 meters, quickly and repeatedly.

At the 50 yard zero range, someone had left a bunch of mostly broken clay pigeons out on the berm – they were quickly reduced to tiny fragments, even from the standing, coming up from the low ready position and firing as fast as I could do so and still be accurate (generally about 1.8 seconds from buzzer to first shot on a whole clay pigeon). The weapon was remarkably soft shooting, especially considering that it was still equipped with the A2 out front.

I think this would make a fantastic weapon for a lot of people. The first-time AR owner would do well to buy a quality product, as would the police officer looking for a patrol rifle. Everyone can appreciate the benefits of a light rifle – regardless of how much they work out, there comes a time when you just can’t keep holding a rifle on a target or a threat with just your non-firing hand, whether that’s 5 minutes or 5 hours. Plus, the excellent balance point offers great handling characteristics. Women, children, and anyone who wants to put rounds on target quickly will appreciate the light recoil which results from the combination of a midlength gas port location and a proper gas port diameter.

There are plenty of ARs out there, but very few can match the quality of the components and the attention to detail that goes in to each and every BCM upper. Of those that can, few offer the benefits of the midlength – sight radius, reduced operating pressures, etc – and the light weight prized by those who have to carry a weapon all day. I can’t say that there’s a market-wide trend towards lightweights, but it does seem that more and more people are realizing what they have to offer. This is, without a doubt, a good thing.

Overlooked Bravo Company MFG Features

Bravo Company has released a ton of information as to what makes their product worth the asking price. I’ve never questioned that – the barrel extension thing taught me plenty – but now there’s plenty of in-depth information as to the quality of the rest of the parts.

Some of it takes a little of the wind out of my “Beyond the Chart” series’ sails (that is, items I’d been planning to cover), but I can’t complain – good info is good info, regardless of where it comes from. Do yourself a favor and check it out.

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