AR-15 Weight and Balance
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, rail panels, and a 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 panels and a 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 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.
ith a CAR stock and the A2 flash hider, the weapon's CG is right at the point of suspension.
Cammenga EasyMag
If you've been using magazine fed weapons for a while, you've probably loaded quite a few magazines. Steel and aluminum AR-15 magazines are not very well known for being easy to load, and while mag loaders are available, I've never felt the need for one - I've just sucked it up and loaded mags the hard way.
This product isn't new, but it does address this issue in a unique way. The Cammenga EasyMag, which is produced in Michigan, features a "sliding body" design that allows the user to slide the mag open, simply drop rounds into the magazine, and then slide the mag closed. At that point, the mag is ready to go. If your fingers and thumbs don't have a whole lot of strength, this may be a good option for you. As an aside, it can be loaded and unloaded just like a standard magazine, and it's remarkably easy to do so.
However, it's not without drawbacks. In order to slide the magazine open, you have to have a certain amount of grip strength - I handed the mag over to the rangemaster, who is in his 60s, and he was unable to get the magazine open. Also, there are a number of sharp edges which can slice you if you're not careful. If you don't load 30 rounds in the mag, or close to it, it may spit out one or two rounds when the follower slams upward. I've found that keeping my palm at the top of the mag when closing it will prevent any rounds from flying out. Finally, rounds may slide out the back of the mag when you're loading #28-30, so it's best to load two rounds at a time, essentially side by side.
Now, on to function. I've destroyed my share of magazines in drop and crush tests, but it wouldn't make sense to do so without ensuring that the magazine works before anything bad happens to it.
I loaded the magazine with 30 rounds of Silver Bear 62gr HP. Previously, I had fired about 150 rounds of this ammunition through the rifle (Spike's Tactical CHF upper, Sun Devil lower) without a hitch, using several different types of magazines. The magazine was fairly easy to insert with 30 rounds in the mag and the bolt forward.
The first round fed out of the magazine just fine, but the second didn't come out of the mag. Here's a picture of an identical stoppage that I encountered with different ammunition. In over 1500 rounds and with a variety of magazines and ammunition, this weapon has never suffered any kind of stoppage - until now.
Interestingly, tap rack bang didn't work with this magazine - not at all. In order to rap the bottom of the mag hard enough to have any effect on the follower or the rounds in the mag, I had to remove the mag from the weapon and slam it down on one of the tables at the range. Later, I was able to hit the bottom of the mag with the heel of my hand about a dozen times, and the malfunction was corrected.
The rangemaster and I then fired the remaining 28 rounds without any problems, however, the bolt did not lock back.
I then fired 10 more rounds of Silver Bear, the last I had brought. The bolt locked back, and continued to do so for the rest of my range session.
At that point, I was out of Silver Bear. I had loaded 100 rounds of 55gr .223, so I switched to that. I fired 5 rounds from a loaded mag of 30 to ensure function, then replaced those 5 rounds, and dropped it on asphalt, directly on the feed lips, from chest height - as if I had fumbled a reload. Here's what the mag looked like.
Other than a few scratches, the magazine looked just fine. I loaded and made ready, and fired the first round. I could feel that the bolt had gone forward, so I squeezed the trigger again...click! I dropped the mag, and here's what I saw.
Again, tapping the bottom of the mag didn't work - I had to slam it on the table.
I was then able to fire the rest of that magazine without and problems.
I loaded and dropped the mag three more times, firing 5 to 10 rounds after each drop, then replenishing the magazine. During one of these strings of fire, I encountered another FTF, which is pictured above.
While it didn't spit out any rounds during the four drops - which is very rare, in my experience - it did cause the rounds to stick out of the mag at odd angles. These problems were relatively easy to fix with finger pressure.
After the fourth drop, I noticed a crack forming at the rear of the right feed lip, on a spot weld.
At this point, I stopped drop testing, and fired the remaining ammunition without any problems.
After I had expended the 140 rounds used for testing, I opened and closed the mag a few times to see if it had gotten any easier to do so. I don't think that it had, but on one of the cycles, I "over-closed" the mag, and this was the result.
It was pretty easy to slide back into place, and I was unable to repeat that issue, but it was interesting nonetheless.
In my opinion, a magazine has one purpose: to work. If it doesn't work, it's not useful. While this mag has many good points - the strength of its spring steel body, for example - the simple fact that I encountered so many stoppages and issues means that I wouldn't use it outside of the training arena. Even if it had functioned perfectly, I'm not convinced that it is very useful for folks with bad joints or weak hands, because it does require a good amount of force to open, although closing the mag is easier. It would certainly be beneficial for those who have to continually load mags over and over and over, such as in a carbine course - but for patrol, duty or combat, magazines should be loaded prior to use, even if that takes a few extra minutes to load the "old way".
My standard disclaimer: I was provided with this magazine, free of charge, for test and evaluation purposes, by someone connected with Cammenga.
Upcoming tests/reviews…
I haven't posted anything in over a week, as I've been pretty busy. However, I've stayed on top of certain things. In the next few weeks I'll be doing .30 caliber AP projectiles vs. multi-hit Level IV plates - in accordance with NIJ test standards, or as much as I can realistically comply with them.
Testing - Cammenga magazine testing, and more AR-15 dirt testing, including starting with the bolt locked to the rear.
Gear - a "war belt" write up, and a more extensive review of an ALICE-frame compatible pack, made by the quality gear maker HSGI, that I've been using for quite a while.
I'll also be talking about some interesting wildcat cartridges for the AR-15 platform, including a .30-caliber wildcat that uses standard 5.56 magazines, bolts, and brass, while exceeding the supersonic performance of .300 Whisper. For someone looking to stretch their AR-15's performance on a budget, especially for hunting or self-defense purposes, this may be just the ticket.
If you have 10 minutes to spare, watch this video.
Every month, MDTS puts out a short video. They've had good things to say in the other videos I've watched, but this month's video will help just about anyone.
I've tried to get across similar points in my blog posts - mainly, avoid confrontation whenever possible, and pay attention to your surroundings - but this is an excellent description of a thought process that might one day save your life.