I believe that this is the best place for this...

[briandg]

I was discussing suppressed rifles a few days back, with the insistence that it be a subsonic round through the rifle.

The guy was looking at .308, which just isn't practical and he knew that. He then looked at .300 whisper and decided on 300 blackout, got the rifle and suppressor, and is hog hunting successfully with it at 150 measured yards.

It brought up a few questions in my mind.

A subsonic round, is, absolutely limited to 1k feet per second, to the only difference you can create in subsonic rounds is bullet mass, caliber, construction, and momentum. This led me to start considering a 240 grain 44 or 45 caliber bullet, at 240 to 260 grain range, at 1K fps, and this is easily achievable with either casull or 44 magnum brass.

My first thoughts were using a bolt, either a pre made ruger 44 bolt, or a short action rebarreled to either diameter and the bolt/magazine modifications. I see no reason that the AR platform couldn't be tuned to work on a .44 magnum cartridge, or a rimless equivalent.

My thoughts would be a special design bullet with a polymer tip for rapid opening, intended to get at least 1 foot of gel penetration. a solid copper with a thin front cavity wall would work.

A prefragmented LEO round could be created with a sintered, crown shaped tungsten core, copper jacket, lead or tungsten base core, and a polymer breaker to open up the front flechettes.

Between 4 and 6 teeth in the "crown" that would break off into 20-30 grain parts would leave at least 100 grains to work into jacket, rear penetrating core, and polymer opening wedge.

So, when considering a subsonic round for a suppressed rifle, we have a .429 or even 454 caliber projectile at 1K FPS, that should be able to do what, 2" groups at 100 - 150 yards? Adapted to an ar platform, this would be a really disabling round, and suppressor capable.

Even in my own little town, urban distances will not exceed 50 to 100 yards. An LE agency could keep a set of both rifles on hand. I see no reason to use a .308 in most settings, when stealth and quiet may offer an advantage.

Our police, for example, used a .243 winchester as the department sniper rifles, rem 700. The .308 may be traditional, but not the only option.

 

[briandg]

No opinions?

I really liked the idea. In various references, the heaviest .44 magnum bullets came in just over 1k fps in the first place, so taking them subsonic isn't too much of a stretch. The ar can be used with a 9 mm round, and unless the cartridge itself is impossible to work with, it should be available there, too.

I'm sure that somebody has already developed a big bullet cartridge for that platform, but if so, what is it, and could it be adapted to suppressor use?

 

[9-ball]

Well, the Soviets already created such a dedicated subsonic round. A bit less taken to the extremes than your example, they put a 260 grain 9mm bullet on a 39mm casing, giving it muzzle velocities around the 280 m/s.

They made assault rifles, sniper rifles and very compact carbines in that calibre for the Spetsnaz and apparently it got very positive reviews (partially because of the great potential for penetration).

You should check out the AS VAL (assault rifle), VSS Vintorez (sniper rifle) and 9A91 (kind of super compact thingy). I wished they exported these things...

 

[jmr40]

I'm not into supressed rifles, but know a few guys who will pay a premium for one of the Ruger 77's that were chambered in 7.62X39. They thread the barrels for a supressor and load heavy 180 gr bullets in them from what I understand.

 

[briandg]

That soviet round looks like a good choice for mid to long range suppressed sniping. As we were discussing, 1 k fps is the limiting factor, and all you can do is boost bullet weight, diameter, and performance to get a better cartridge. I'd hate to be depending on a 150 grain 30 caliber at 1k. It's not the same as a tactical load in a .308 at almost 2,600 fps.

That 260 grain 9mm slug would be flatter and more accurate than a 44 caliber, and have a much better range. Will it destabilize on contact? sure seems that it will punch through and break dance through the target's entrails like an angry badger.