300 Blackout SBR

[3strucking]

I would like to keep length at a minimum since this is going on a 10" barrel sbr. My options are a reflex design or using some 1.750" OD tubing to keep my length down. Whats the consensus on the two? Its going on a gas gun and will probably shoot supers mostly.

[T-Rex]

Since length trumps all, why not use a shorter barrel and reap the reward of fitting a longer suppressor? The 300blk was meant to run a pistol gas system w/ a shorter barrel. An 8" bbl, with an 8" suppressor, would net a <carbine length gun.

[3strucking]

If I use a shorter barrel, I might as well build a integral. I was just trying to find the best option for the upper I have. Thanks for the reply

[3strucking]

If more volume and a overbore on the baffles is good for a gas gun, could you not get good results with a large diameter short, can vs a smaller tube, more baffles? have any SOT's here experimented with this?

[ECCO Machine]

If more volume and a overbore on the baffles is good for a gas gun, could you not get good results with a large diameter short, can vs a smaller tube, more baffles? have any SOT's here experimented with this?

Yes, we have, and all else being equal, shorter cans will never suppress as well. You cannot think of suppressors in the same way as transferring static pressure from smaller to larger containers in a closed system. Boyle's law does apply to a degree, but there is a time component; within reason, a longer & thinner tube will suppress better than a short & fat one of equal internal volume because there is more time for it to do what it does before the bullet leaves.

That said, there's no reason a 6" long 1.562 or 1.625" can shouldn't be able to put down mid-high 130s on both ends on a 300 blk with supers. You'll be disappointed with subsonic levels compared to a tuned gun with an 8"-9" can, but it doesn't sound like that's of much concern to you.

[3strucking]

I want to keep the overall length to a minimum. I think I will order another barrel and go from there. Thank you all for the help.