blow back and gas system length on AR platform

[noisecatcher]

Can anyone tell me if there is a correlation between blow back and the length of the gas system?

For example if you are looking at 16" long 300 blk barrels and you have the option between pistol length or carbine length gas system would one give you less blowback than the other while running suppressed? I'm talking about a DI gas system not piston driven.

Also is there anything you can include in suppressor design that will minimize blowback. As I understand it blow back is just gasses taking the easiest route to free space through the gas system and ejection port so it stands to reason that a free flowing suppressor would have less blowback, with the trade off of less dB reduction. Do I want 2 things that you can't have together in a basic form1 suppressor? ( best dB reduction and minimal blowback)

[Samson104]

The rife length will give less "blowback" than the pistol length with and without a suppressor.
Every commercial AR I've ever seen was badly "over gassed" meaning the barrel port and gas system allows alot more gas into system than needed in an effort to increase reliability. On a working gun i'd leave it alone and just add a gas buster charging handel. But for the guy not protecting his life with it id suggest getting an adjustable gas block and tuning it to run whatever you want. Noveske makes a really nice one call the switch block.
My 20" AR stays suppressed with a tight bore suppressor that generates alot of back pressure , adding an adjustable gas block and gas buster charging handle it produces WAY less blow back than any factory 16" AR I've ever shot

[Wicked]

Adding a carrier weight will help as well.

[curtistactical]

Stick with the pistol gas system on 300blk. its the only length I use for 300blk. no matter what the barrel length is. A larger blast chamber on the suppressor will usually help with blow back and the gas buster handles work good. I just saw silencerco is making a bolt carrier for suppressed AR's that is supposed to reduce blow back but I have yet to try one but it sounds promising.