ok so I was looking on gunbroker for a 300 blackout upper and ran into and offer (see below) my question is how come a Stainless Steel Pistol Gas System  on a long barrel?  my understanding is that its better to have the pressure from the propellant pushing the projectile as long as possible before returning to the BCG to cycle.  I guys what I am asking is what is the rational for having a pistol gas system on a long barrel?

Live Free Armory 16" .300 Blackout Upper



Caliber                      .300 Blackout
Barrel                         16" .300 Blackout Barrel with 1/8 Twist 4150 Chrome Moly Vanadium Steel QPQ Corrosion Resistant Finish
Gas System               Stainless Steel Pistol Gas System
Muzzle Device           5/8x24 A2 Flash Suppressor
Handguard               15" Live Free Armory Signature Free-Float Keymod MIL-STD 1913 Rail System
Upper Receiver          Forged 7075-T6 Aluminum Flat-Top with MIL-STD 1913 Rail
Forward Assist          Yes
Dust Cover                Yes
Gas Block                 4140 Steel Micro Low Profile Gas Block
Finish                     Type 3 Hard Coat Anodized
Overall Length          24.5"
Weight                   3lbs 4oz
Bolt Carrier Group  Premium LFA Nitride Full Auto Mil-Spec HPT/MPI
Charging Handle       Mil-Spec Charging Handle
Warranty Limited Lifetime Warranty

 

You will have better luck and reliability cycling subs with a pistol length gas system

so you are saying that this is typical good setup for running 300 blackout?

so you are saying that this is typical good setup for running 300 blackout?

Short answer, yes. Having the pistol length gas system is the best compromise for being able to use both super and sub sonic ammunition and have it function reliably. It also has some to do with having to use a much faster burning (magnum pistol) powder compared to the usual slower burning rifle powder.

I agree with everyone. Pistol gas system is best and te nitride f/a bcg sounds good. Everything else is pretty much standard (except handguard rail, dunno what it looks like) and I'm sure they headspace it for you since it's a complete upper. That's the bonus for buying complete upper.

Carbine gas system can work, just got to open gas port larger, I think .101-.105". For subs .

You are correct on your understanding for longer barrel length equals softer shooting with a longer gas system. Can be negated by other means though such as gas port size, buffer weight and stronger buffer spring combined with a f/a bcg. But 300 blkout is weaker than 5.56. If you look at the boxes velocity and ft lbs of energy it's not very strong. Subs usually have 700-900 tops of ft lbs of energy. Just a bigger hole. Vortx has a good round for hunting. 110 or 115g I forget.

Short answer, yes. Having the pistol length gas system is the best compromise for being able to use both super and sub sonic ammunition and have it function reliably. It also has some to do with having to use a much faster burning (magnum pistol) powder compared to the usual slower burning rifle powder.

if you are only going to be shooting supersonic, then it is ok to have a carbine length gas system
if doing subs, you are likely going to have to play a lot with your loads, buffer weight, and buffer spring to get it to cycle and lock back reliably with a carbine length

From what I've seen, most using both super- and sub-sonic ammo in 300Bk have an adjustable gas block installed.  Then they can select whether the gas system gets more or less blowback to cycle. 

Not only will the ammo type change the cycling, so will use of a suppressor.  Suppressor + subsonic ammo is a common combination for 300BK, as is supersonic ammo + unsuppressed.  Having a gas block that switches between the two is a good solution.

If you plan to shoot subs get a pistol length gas system. You will most likely need a can to increase the back pressure. However, as you may already know suppressors aren't legal in Hawaii. I've seen pistol length gas systems work for subs with an adjustable gas block, but it's a pain especially if you plan to use reloads.

If you plan to shoot supers (most likely), go with a Carbine length gas system. I have a Carbine length 300 at .750 it cycles supers fine without any ftfs.

In short, do you plan to shoot subs, supers or both? IMO it's pointless to shoot subs without a can.

In short, do you plan to shoot subs, supers or both? IMO it's pointless to shoot subs without a can.

many members of this forum successfully load subsonic 300 black in a pistol length gas system without adjustable gas blocks
we've only found subs finicky in carbine length

many members of this forum successfully load subsonic 300 black in a pistol length gas system without adjustable gas blocks
we've only found subs finicky in carbine length

Many?? I recall only one person saying that they use a pistol length gas system without an adjustable gas block.

Yes, subs will be finicky in a Carbine length gas system read my previous post about wanting to shoot supers in a Carbine length gas system.

Yes, many here and on larger forums too




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