The Pros and Cons of Ultra-Light AR15s

Over the last few years everything new and improved on an AR is about weight. Custom, production, you name it, first thing they all seem to point at is how much it weighs or how many ounces were saved.  This is not necessarily a bad thing, but shaving weight while compromising other factors can be detrimental, and often expensive. If you need it great, but if not it may be better to save the money rather than risk failure for a few ounces of weight.

If all your rifle does is sit in a case, safe, or trunk until its carted to the bench there is not much need for an Ultra-Light AR. Carry it all the time, work entry drills constantly and it makes a huge difference. Holding that rifle in the pocket gets tiresome, add night vision, lasers and other gadgets and it’s worse. Shooting one handed is another serious advantage.  Carrying something for miles on a hunt or “recce” and you discover very quickly that weight is a factor. They really shine at competitions where speed is everything. Getting old, not as strong, or better yet bringing them to the next generation. In general, less weight benefits everyone, so long as it does not compromise reliability and durability and that’s where it can be an issue.

Too much of a Good thing?

The lighter the rifle the greater the felt recoil, not an issue with 5.56mm most of the time, but for some it is. Recoil can be mitigated with brakes, but that adds a whole other set of issues. You can add a suppressor, but that adds a pound or so to the rifle and may compromise reliability. Tuning to make sure it is not grossly over gassed is a big help, but in the end the laws of physics prevail, light rifles will have more felt recoil. 

Over the years I have seen several very high dollar AR’s with super lightweight hand guards crack or break where they attach to the upper. I have also seen light weight upper receivers crack at the same spot. Most of these look like swiss cheese with more holes than substance, but it is popular. If you never add anything to your hand guard, lean into a barricade or obstacle, or set a bi-pod hard you are probably fine.  If you do, be very careful about trading weight for durability. Can you have both, maybe, jury is still out on that one.  Either way doing so tends to add to the cost.  Exotic materials are seldom “cheap” and spending another grand to save two or three ounces is just not necessary for most. All the weight savings in the world is useless if your rifle breaks in a fight.

There are only a few places substantial weight can be saved, the two most common are barrels and bolt carrier groups. Both come with their own set of issues, put them together and it can be a nightmare. Thin or heavily fluted steel barrels shed pounds without a huge cost increase.  Carbon wrapped barrels are great, they can just be three times the cost or more. Thin barrels tend to see impact shift when they get hot, so they are less suited to select fire, or rapidly sustained fire where accuracy or increased range are needed.  Having experienced consistent accuracy with both fluted and carbon wrapped barres it can be done, but generally at a cost. Barrels in general are far more accurate than in the past, but going too thin or too light can still cause issues.

Bolt Carriers are being made lighter including those made from Titanium.  When they work they are very soft shooting with less reciprocating mass.  On the down side they can be picky about ammunition and you really need to use different buffers and springs. The rifle must be tuned, you just can’t throw them together.  Stoners DI (Direct Impingement) gas system is all about gas at the port, the mass of the BCG, and how fast it returns. Drop all that weight and it’s a dance getting it worked out. You may get lucky, and it works, more likely not, and only with the ammunition its tuned for. Even a pure range toy is no fun if it won’t work, but for duty or self-defense rifles it’s not the best choice.

The rest is just shaving weight where it does not matter, in the receivers, hand guard, stocks, grips, muzzle devices, anything that attaches to the rifle. Cuts and indentations in lowers and uppers where strength is not required.  It’s a balancing act since you don’t want to weaken the rifle.  Titanium, polymer, magnesium and other materials can be used, most are very costly and do not always hold up under very hard or consistent use.

So what is Light?

It really is all about who you are and what you do with the rifle. To a soldier a 6.5 pound rifle is light. In most cases these rifles are work horses, design is all about reliability and durability in the field first, weight savings is important but never at the expense of the other.  Any weight loss is good, but seldom is it substantial since it simply cannot compromise durability in the field. Move into the Special Missions Units and now you add lasers, lights and optics to the equation.  Ultra-Light rifles are just not in the cards, at least not yet.

So, what’s Ultra-Light Weight? For the most part 5 pounds or less on a bare rifle, a full 1.5 pounds lighter than a standard M4, a pound lighter than most “light weight” AR15’s. Most weight comes from the barrel and bolt carrier, followed by accessories.  Anyone using a “standard” weight rifle will notice the difference immediately. Take it to an intense class and you will really notice it, so long as it works. That is the rub, they tend to cost more, and seldom seem to make it much past day two of the classes we teach at Gunsite Academy. Lost track how many of these rifles that “never failed” or were “flawless” took a proverbial dump two hours into the class. Unfortunately, these are often the most costly and least reliable.  Not always, having tested a few they can be made to shoot well under hard conditions, but they are not cheap and I have never used them with anything but an optic, BUIS and a light. The most reliable and least problematic all seem to strike that middle ground.  

Moving to the Middle

Listed weight of a military issue M4 (14.5” barrel) is around 6.5 pounds. For those still issued M16A2 rifles it’s just over 7 pounds.  Move to the newer piston rifles like the HK416 and you are around 7.5 pounds. On the DI guns it is pretty easy to get closer to the 6-pound number with changes that maintain durability and reliability, under 7 pounds for piston rifles.  It generally requires a carbon wrapped, fluted and / or contoured barrel. BCG remains steel insuring reliability, and you remove the rest using either a shorter barrel or “lighter” weight receivers and components. A pound or even half a pound can make a huge difference when you are lugging a rifle around or shouldering it for training, duty, or operations.  There are several hand-guards out there that are much lighter and lose very little structural integrity. Titanium is great just so long as it is not too “skinny”. It also works for buffer tubes and other components.  Most well-made AR’s in the 6-pound range remain reliable, durable, and accurate. 

Keep it Simple

Don’t put anything on your rifle you will never use, most need high quality optics (or dots), back up sights a sling and a light. Leave the bipod in the bag unless you need it. Pistol grips, barricade stops, rails and similar items are useless weight in most cases. It’s amazing how much of this stuff gets shed at lunch on day one of an intense rifle training; by day three it’s a rifle, sling, optics, and ammo. Best rule of thumb is to start bare, add only what you need and no more. Run a 20-round magazine, carry the 30 rounder as a spare. Suppressors are great, but they add 5” and around a pound. Use a high-quality flash hider or one of the newer combination devices that don’t destroy your hearing. If you can legally run a 10.5”-11.5” barrel, do it.  There is very little (depending on the shooter nothing) a 16” barreled 5.56mm AR will do a 10.5-11.5” won’t and nothing shaves weight like removing 6” of barrel.  

Bottom Line            

If it’s just for kicks, do whatever, at least for now we remain a free country and you can spend money as you see fit.  If it is a lifesaving tool, consider the middle ground. Lighter is not always better and in certain circumstances can be a real issue. Spend your hard-earned money on what will net the most value. Sometimes the money saved not going super light is better spent on ammunition and training. In fact, in most cases money is better spend there.  A slightly heavier rifle wielded by a well-trained shooter will always win out no matter what, so spend wisely and train hard.

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