Photos and Video: New Subsonic ARs from Beck Defense


Some things aren’t supposed to work.

Things like jumbo jetliners actually flying, any electronic product the day after the warranty expires, and AR-pattern rifles that are actually subsonic.

At a recent Lancer Systems media event, I was proven wrong about the subsonic AR rifle part, although I’m fully confident my Clapper light switch will break next Tuesday. Beck Defense was in attendance with some innovative subsonic AR-10 and AR-15 rifles. Let’s take a quick look at a couple that piqued my interest.

5.56mm Cycling Subsonic Rifle

Most people are by now familiar with 300 AAC Blackout rifles. Those work with standard AR-15 lowers, bolts and carrier groups, and uppers, with the obvious exception of the barrel. Based on a cut-down 5.56mm case, they take a .308 bullet but use the same old AR-15 magazines. 300 Blackout can be loaded with heavy .308 bullets and run at subsonic velocities, or it can fire lighter bullets at supersonic velocities.

Beck Defense 5.56mm Cycling Subsonic
Beck Defense’s 5.56mm Cycling Subsonic Rifle.

The Beck Defense rifle is not a 300 Blackout, although they make those too. The one I’m talking about is a regular 5.56x45mm/.223 Remington AR-15, but tweaked to fire subsonic bullets. This rifle is designed to fire 75-grain, .223-caliber projectiles below the speed of sound. Can you say “perfect ‘indoor activities’ rifle?” Whether you’re a professional door-kicker or interested in home-defense options, it’s a pretty incredible solution that’s not supposed to work, but does.

Normally if you first don’t succeed, you just get new batteries. I think the Beck Defense engineers tried a little harder than that, as they had to tweak both ammunition and rifle to get a functional platform—and functional it is. In fact, it’s so functional that the 5.56mm rifle will operate reliably in full-auto. It has to have a suppressor to function properly, but that’s the whole point, right?

In this case, the rifle and ammunition are custom-made to work reliably together. This means you need to get the ammo directly from Beck Defense. At this point, there’s no word as to whether other ammo manufacturers will produce compatible offerings. I wouldn’t count on it, as there is some top-secret proprietary engineering going on here. Beck Defense has an existing model of this rifle that operates via direct impingement like a standard AR-15, but it’s limited to subsonic use only. They’re working on a third-generation model that will handle both subsonic and supersonic 5.56mm loads. The model we shot at the Lancer event features an adjustable gas knob that allows the operator to switch between supersonic, subsonic, and off.

Beck makes custom 75-grain ammo to run this rifle.
Beck makes custom 75-grain ammo to run the 5.56mm rifle.

It runs like a champ in full-auto. We took full advantage of that capability at the range and giggled like school girls the whole time. I shot a rough range video that’s embedded below so you can see it run.

The “Gen 3” rifle will be launched at SHOT Show in January and be available sometime during the first quarter of 2016.

An adjustable gas system supports supersonic, subsonic, and no gas operation.
An adjustable gas system on the 5.56mm rifle supports supersonic, subsonic, and no gas operation.

The .510 Beck rifle

As if the subsonic 5.56mm rifle was not enough, we had the opportunity to fire an even newer and badder rifle. Built on a basic AR-10 platform, Beck brought out a completely new rifle chambered in a proprietary cartridge—.510 Beck.

As it's built on an AR-10 platform, there's a bigger mag well and upper receiver.
As it’s based on the AR-10 platform, the .510 Beck rifle has a beefier magwell and upper receiver.

The .510 Beck cartridge is intended to be used with the AR-10/.308 platform, not the smaller AR-15/5.56mm. As the AR-10 is designed to handle larger .308 cartridges, there’s more room in the magazine and chamber. With larger cartridge-case capacity for powder, clever people can start to do clever things. 510 Beck can launch a 300-grain projectile at up to 1,900 feet per second. The .510 Beck will be like a 300 Blackout on steroids, offering a wide range of supersonic to subsonic capability. For example, a lighter 140-grain bullet will hit 3,000 feet per second. On the complete opposite end of the spectrum, a 690-grain projectile can run from the same rifle at subsonic speeds.

As the lower is a standard AR-10 platform for .308, the company envisions military applications in which a user can carry the .510 Beck upper for specific mission requirements when .308 just won’t do. Some magazines in a load would be stocked with .308 while others could be loaded with the desired variations of super or subsonic .510 Beck cartridges. Lancer is building the magazines that make it run, and it looks like they will be 10-rounders.

I had the opportunity to shoot that 690-grain Buick engine block (using a suppressor, of course) and it was surprisingly mellow. I guess the enormously heavy bullet is moving slowly enough as not to cause significant recoil. I would describe it more as a gentle shove.

I expect we’ll hear a lot more about this at the upcoming SHOT Show in January. We’ll be sure to keep you informed.

Note added 3:23 p.m. 10-19-2015: This article’s text has been corrected to indicate that .510 Beck is a proprietary cartridge.

Tom McHale is the author of the Insanely Practical Guides book series that guides new and experienced shooters alike in a fun, approachable, and practical way. His books are available in print and eBook format on Amazon.

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