BulletProofMe.com Level IV Armor Plate Test Monday, Jan 18 2010 

Tactical Gear and Tests 87gn 7:38 pm

Last year, I purchased a set (front and rear) of Level IV plates from bulletproofme.com.

They fit just fine in my Interceptor, but when other plate carriers were used, the rear, which was countoured differently than the front, would not fit.

Even after I had owned them for 6 months, the company offered to swap out the rear for a front plate (for a 20% fee – very reasonable in my opinion, since they would have had to X-ray the plate before reselling it).

However, I decided to test the plate myself, and see if it really did what they claimed – stop multiple shots of .30-06 armor piercing ammunition without any supporting soft armor.

Here is a video of the test.

The plate did indeed stop 3 shots of .30-06 AP (163gr hardened steel penetrator projectiles courtesy of Rich_V on AR15.com), as well as many other rounds.

The plate allowed part of one .308 projectile, as well as 4 5.45×39mm projectiles, to penetrate.

However, these hits were in rather close proximity to other impacts. Because this was a ceramic plate, the initial impacts fractured the plate (it’s designed to absorb the impact this way) and the later projectiles “slipped through” the cracks.

Even after it had been shot over a dozen times, and it had literally come apart, it still stopped XM193 5.56×45 and a 12ga slug.

Overall, I’m very impressed with the performance of this plate, especially considering the cost ($270). I’d still probably wear soft armor underneath the plates, given the chance, but at least I know that the plate exceeds the manufacturer’s claims.

 

AR-15 Weight and Balance (Part 1 of 3) Wednesday, Nov 25 2009 

Firearms and Tests 87gn 12:07 am

On the internet, the debate rages on.

What is the debate? Well, it doesn’t really matter. People will seemingly argue over anything – and I’ve been guilty of that myself.

One of the more popular debates is weight. Proponents of lightweight rifles point to carbine courses where a heavy rifle can get tiring, and accessories that boost the weight of the rifle, meaning that starting with a lightweight carbine is better. Proponents of heavy rifles say that they work out a lot, and their grandfather carried a BAR while assaulting the beach at Versailles, so weight isn’t a problem.

Another topic is balance, and this is a term that I have yet to see defined by a majority opinion. Some people like the weight to be on the front of the rifle. They load up their rail system with lights, VFGs, bipods, etc, over a heavy barrel profile, and with a standard or lightweight aftermarket stock out back. Others like a rear bias – they’ll get a Magpul UBR and stick it on a lightweight rifle with a pencil barrel and a pistol light on the handguard. Finally, some prefer a neutral balance – like myself (although I do prefer a very slight rear weight bias).

Before I dive into the meat of the issue, I’ll define something. Center of gravity (CG) – and if you’re a pilot, you’ll know what I’m talking about before I say it – is the point at which something will balance if it were suspended from that point. This is easier said than done, but with the AR-15, I’ve given it my best effort.

With an airplane, fuel is normally located at a point near the center of gravity, so that the flight characteristics of the airplane do not drastically change from the beginning to the end of the flight. Similarly, the cartridges in an AR-15 magazine are located at a point which is essentially right on the center of gravity of a stock M4 carbine. Thus, as the ammunition is expended, the balance of the rifle does not really change. What this means is that whether you’re firing the first round or the thirtieth, you won’t have to compensate as you bring the rifle up to a firing position.

With a CAR stock, CAR handguards, and the A2 flash hider, the weapon's CG is right at the point of suspension.This is my definition of a "neutral" CG for the AR-15.

This rifle weighs almost 2lbs more, but has a nearly identical center of gravity. How? Properly balancing the weight of accessories up front with a heavier stock at the rear.

You may not notice it without someone telling you to look for it, but if you have a forward weight bias – meaning that you’ve moved the center of gravity forward from the “stock” position – as you expend ammunition, the weapon will become slightly more nose heavy, because weight is being reduced at a point behind the CG, thereby shifting it forward.

Whether you have two rifles or twenty, maintaining a consistent center of gravity will help you shoot better when switching from weapon to weapon. Incidentally, when starting out on this project, I discovered that all of my AR-15s had almost exactly the same center of gravity, although weight varied as much as 4 pounds from lightest to heaviest.

Now, aircraft CG does not directly relate to weapon CG, because you’re putting different forces on a rifle while shooting it than you would on an airplane by flying it, but the basic principles remain the same. Furthermore, I won’t go into the details of aircraft weight and balance – weight, arm, moment and all that jazz – but I will explain what you need to know to fine tune the balance of your AR-15 to something that might be more agreeable to you.

First, understand that the closer the weight is to the center of gravity, the less effect it will have on the location of the CG. To demonstrate this fact, observe the following pictures.

Here, an A2 flash hider is exchanged for a Smith Vortex flash hider. The weight difference is .05lbs.

A tiny change in the attitude of the weapon. Now, watch as a magazine is inserted:

The only change made was the addition of a Magpul PMag with 28 rounds of 75gr ammunition – because the suspension point was slightly forward of the CG (note the muzzle high attitude), there was a tiny change in the attitude of the weapon. That magazine weighed 1.2lbs on a postal scale.

From this, we see that adding weight close to or on the center of gravity will have little effect on the balance of the weapon compared to adding weight farther away from the CG. Because I like to put my optics right at that natural CG, it doesn’t matter whether I have an Aimpoint or EOTech or even a 1-4 variable – the balance of the weapon will basically be unaffected.

Now, let’s see how other parts changes affect balance.

Adding a KAC M4 RAS, TangoDown SCAR rail panels, and a TangoDown stubby VFG shifted the weight forward slightly. Alone, the M4 RAS was, at .55lbs, .25lbs heavier than the CAR handguards and .15lbs heavier than MOE handguards; with TD panels and a TD VFG it weighed .85lbs.

The addition of a Vltor EMod stock shifted the weight to the rear significantly. This is because the CG of the EMod itself is way at the rear of the stock – so even though it doesn’t add much weight to the rifle in an overall sense, it does have more of an effect on CG than other stocks. In other words, if you want to balance out a front-heavy carbine without making the weapon a lot heavier, the EMod is for you. Some applications may still call for a heavier stock, though.

Swapping a rail panel (.05lbs) for a Surefire X300 (.25lbs) brings the nose down slightly…

The additional .05lbs of a Surefire G2 and polymer mount (.3lbs) bring the nose down just a little more (note: a metal head and metal “clicky” tailcap will add .05lbs each)

Finally, the .6lbs of a Surefire 9P in a Vltor offset mount bring the CG back to “neutral”, almost.

I brought another rifle and tested it (without optics) – with a VCAS sling utilizing QD swivels, the rifle was neutral…

Without the sling and the swivel at the rear of the stock, the nose of the rifle dipped a little. The forward swivel was mounted at the rear of the rail, so it had little effect on the CG. Yes, this rifle had a Daniel Defense M4 12.0 rail, Surefire G2 LED, Magpul MBUS front sight, several rail panels, and a TD stubby VFG. How did it balance almost the same as the other 16″ M4 profile rifle with an EMod in the same position? Well, the Vltor low profile gas block is much lighter than the standard FSB, the QD socket at the rear of the rifle helped, and the PWS FSC556 is a tad lighter than the Smith Vortex. Those minor changes allow me to drive the rifle with a “better” VFG position and increase the sight radius without significantly affecting the balance of the weapon.

You may be getting the impression that these changes aren’t making a very big difference. However, if I installed a RAS, VFG, light, etc and left a CAR stock at the rear, the muzzle device would practically be on the ground. Every change I made was very slight and designed to have a small effect on the overall balance of the weapon. I’d also like to note that the collapsible stocks were set at comfortable shooting positions for me – your stock usage may vary, and you should balance your rifle accordingly.

In Part 2 of this article, I will do more fine-tuning of CG relative to weight and intended usage, and in Part 3, I’ll hit the range and compare forward, neutral and rear balanced carbines.

ith a CAR stock and the A2 flash hider, the weapon’s CG is right at the point of suspension.

 

Use of the AR-15 in Dirty/Dusty Environments Saturday, Oct 24 2009 

Tests 87gn 8:11 pm

Recently, a news story broke about US weapon malfunctions during firefights in Afghanistan.

For many, this was a chance to renew their attack on the supposedly faulty Colt M4s in use by our troops overseas. For others – mostly, the troops who had been overseas with the weapons – this was something to scratch their heads about.

My experiences with issued Colt M4s, M16A2s and FN M16A4s were nothing short of stellar. Despite claims – mostly by the uninformed – of constant maintenance requirements, I only cleaned mine when the outside turned brown. I properly lubricated my issued rifle, and I was also lucky to have a good armorer who made sure that my rifles had parts replaced when necessary. I made sure I had good, working magazines. As a result, I was rewarded with exceptional performance from my M4. I had similar results with my M249 SAW – though I spent far more time maintaining that weapon.

So I’m always a little suspicious when I see claims of M4s going down in combat.

One of the biggest problems is when Soldiers and Marines try to use their rifle in a manner other than that which was originally intended. As I was taught by an 0331 (Marine machine gunner) during a crew served weapon course, “You are there because the rifles have failed.” In other words, machine guns lay down suppressive fire, enabling the rifles to take precision shots, or at least aimed fire at the enemy. When this doctrine breaks down and everyone goes cyclic – that is, firing as many rounds as they can, as fast as they can – either everyone is going to run out of ammunition, or machine gun barrels are going to overheat and warp, or rifle barrels are going to literally split. When things get really hairy, rifles and machine guns are going to be disabled due to enemy rifle, machine gun and RPG fire, as well as indirect fire from mortars and rockets.

Now, the issues here go beyond weapons. The Soldiers were forced to defend themselves against a much larger force that was attempting to suppress the main group of Americans in order to (presumably) capture a few at an observation post. They had no air or arty support, and their leaders apparently didn’t make friends with the local populace – this resulted in the deaths of 9 American Soldiers. Their actions that day in the face of an overwhelming force were heroic, and their sacrifices will not be forgotten.

Unfortunately, an incorrect thought process persists among many officers and senior enlisted – that the rifles should be scrubbed clean as often as possible, and that oil should not be added to the weapon, for it will “attract dust and dirt”. Soldiers and Marines have been dying because of this absolute garbage since the introduction of the Garand in combat operations in the Pacific during WWII. Proper lubrication is vital for any semiautomatic or automatic weapon. I learned that lesson today with my Glock 26 pistol, which had some dirt inadvertently thrown on it during the following test. It malfunctioned 6 times in one magazine before I disassembled it and properly oiled it, as I had been negligent in keeping it lubricated. After that, it functioned perfectly.

Now, with that discussion out of the way – if I were to redeploy to Iraq, or deploy to Afghanistan, I’d feel very well equipped with a Colt M4.

To demonstrate why, I made a short video today while I was at the range with a friend. The rifle in this video is composed of a Smith & Wesson M&P15R upper in 5.45×39 caliber on a cheap forged lower. The upper receiver assembly has been modified from stock – the bolt and bolt carrier, as well as the muzzle device, have been electroless nickel plated for corrosion resistance. The lower receiver, as well, has had its internal parts electroless nickel plated. I use a Spike’s Tactical ST-T2 buffer, as the surplus Russian ammunition used in the test is fairly hot. The rifle was properly lubricated with FP-10.

CProducts, LLC, makes the only 5.45 AR-15 magazines. Unfortunately, they are poorly designed and manufactured, and I modified another magazine follower to work in them – although capacity is reduced to 28 rounds, they now function flawlessly. The followers I used in this test were actually my rejects or seconds, and that is why the bolt was not held open after the last shot in each mag.

112 rounds were fired in almost exactly 1 minute, with no malfunctions.

I would have felt confident repeating the test and would expect similar results, but the weapon was getting very hot – the vertical grip was hot to the touch, the receivers were almost too hot to touch, and the barrel was blistering hot. This test was not a realistic demonstration of how a rifle should be used in combat, but rather a demonstration of what the rifle is capable of when stressed to the limit.