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Optimal Gas system length for Suppressed AR?

Discussion in 'NFA Firearms and Accessories' started by Dr.Zubrato, Jan 29, 2013.

  1. Dr.Zubrato

    Dr.Zubrato Well-Known Member

    I've been thinking on and off about suppressors, and everyone who has one talks about increased back-pressure, fouling, and etc.
    So is there an optimal gas system configuration to decrease these nasty side effects, or is this just a fact of life for suppressed AR's?

    For example, wouldn't a rifle length gas system on a 16" barrel like a dissipator design prove to be a better system running suppressed than say a mid length gas system on a 16" barrel?

    Is it worth to have a dedicated suppressed upper, specifically for this purpose or is the extra fouling overstated?

    Just wishing I had a suppressor :)
  2. taliv

    taliv Moderator

    extra fouling is NOT overstated :) suppressors make the guns filthy (and it has nothing to do with DI vs Piston)

    not sure about dissy, but several companies have done a lot of engineering and research on this and that's one of the reasons noveske's switchblock / barrels are so popular.
  3. Sam Cade

    Sam Cade Member

    What is the suppressed port size on a switchblock?
  4. JustinJ

    JustinJ Well-Known Member

    I'm not sure what you're saying but it's my understanding, based on operation, that fouling will be more severe with a DI gun. I know some will argue that in a piston gun you only change where the fouling goes but due to rapid gas pressure build up before the piston rod i don't believe there will be an equal amount of fouling deposited in the piston housing or gas block as would go into the receiver of a DI.
  5. taliv

    taliv Moderator

    the fouling enters the action through the chamber as a result of longer higher pressure at the muzzle (where the suppressor is suppressing). (so having a pistol doesn't stop it)

    it is very simple to confirm. simply shoot a few rounds suppressed and unsuppressed and look at how much dirtier your brass is when shooting suppressed.

    even my pistol brass is dirtier when shot suppressed
  6. JustinJ

    JustinJ Well-Known Member

    Yeah, i realize gas does come back through the chamber and have certainly observed this on my brass as well but i would think additional fouling would come back through the gas tube on a DI. How much i can't say and i suppose it may be negligible. My AUG is piston driven certainly does gag me when shooting suppressed but i always suspected this was mostly due to the location of the action relative to my face since its a bullpup.
  7. taliv

    taliv Moderator

    well, yeah it's at least higher pressure in the gas tube (not sure how much more volume) as the action cycles noticeably harder and reducing the flow through the gas block (e.g. with the switchblock) solves that problem.

    but... even with the switchblock you still get dirty brass and gas in the face.

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