why would i not want piston on a 300 blk?

[ben589]

What are the primary advantages / disadvantages of gas vs piston on a 300 blk SBR?

I'm thinking now between 8 and 10" barrel non suppressed to start with, and both subsonic and supersonic.

[jason]

The only advantage I know of is is it keeps gas out of the chamber. So the parts stay cleaner, and maybe last longer. That's good with the 5.56, but 300BLK doesn't seem to produce as much crap, so it might not be as advantageous here.

The big disadvantage is complexity. pistons add more parts, which means more stuff to clean, maintain, and to break at the worst time. I have an LWRC piston-driven AR in 5.56. The cup that aligns the piston with the piece in the upper snapped. It was two weeks and $15 to replace (with shipping), and without it, the gun didn't cycle properly.
The minor disadvantages of piston are weight and price.

[300Blk]

Pistons cost more, weight more, and are generally louder. They need more special parts, and when you use a can, the junk goes back through the bore on either anyway.

[ben589]

Ok, fair enough.

[trenttyre]

Robinson Arms will be releasing their XCR in 300blk soon, that is a piston gun that would be worth looking into.

I have also heard rumors that an AK manufacture might be releasing a 300blk gun in the near future but I dont see that happening anytime soon.

You could always go buy an SLR106U and have it converted to 300blk like Rsilvers did. That thing was pretty cool.

[d00d]

If you are running suppressed there is a significant difference between direct impingement and gas piston.
The suppressor manufacturers that post sound pressure ratings are doing so for at the muzzle.
However, there's a different rating at the ear, see silencerforum's sound testing forum for tests that show both muzzle and ear.
For DI there is unsuppressed high pressure gas coming back through the gas tube to cycle the bolt.
So for a suppressor that rates well at the muzzle, it could be at least 6db higher at the ear, which is twice as loud.
There is also some lower pressure gas coming back through the barrel due to back pressure from the suppressor as the cartridge is being extracted, but it should be relatively equal for a given suppressor between DI and GP.
GP has the advantage of easier cleaning.
Both will have carbon fouling around the bolt, but DI will have more fouling due to the routing of gas through the bolt carrier.

300 BLK subsonic is the cartridge I've been waiting for after retiring my AWC suppressed 5.56 M16 to the safe 17 years ago.
Now I will be able to get an ear safe 126db or lower, which is around 3 seconds exposure per 24 hours, thanks to Robert and the crew at AAC, Adams Arms, and Griffin Armament.

[trenttyre]

300 BLK subsonic is the cartridge I've been waiting for after retiring my AWC suppressed 5.56 M16 to the safe 17 years ago.
Now I will be able to get an ear safe 126db or lower, which is around 3 seconds exposure per 24 hours, thanks to Robert and the crew at AAC, Adams Arms, and Griffin Armament.

I was under the impression that adams arms scrapped the 300blk piston project.

[d00d]

300 BLK subsonic is the cartridge I've been waiting for after retiring my AWC suppressed 5.56 M16 to the safe 17 years ago.
Now I will be able to get an ear safe 126db or lower, which is around 3 seconds exposure per 24 hours, thanks to Robert and the crew at AAC, Adams Arms, and Griffin Armament.

I was under the impression that adams arms scrapped the 300blk piston project.

I don't know what their current plans are, but I will be using the pistol length kit and subsonic only, and assume at least one of the two ports would cycle the action with the right force.

[Predator Strikeforce]

What about for a lefty shooting a suppressed 300 BLK sbr AR with a Suppressor? Would the piston system make life better for me due to the cause and effect of exploding gas in my face? Just a thought.

[trenttyre]

What about for a lefty shooting a suppressed 300 BLK sbr AR with a Suppressor? Would the piston system make life better for me due to the cause and effect of exploding gas in my face? Just a thought.

well you could get one of the new rock river lefty uppers and just switch out the barrel. they might even sell stripped uppers