Is over gassing a dirty word?

Discussion in 'Silencers' started by Le 901, May 10, 2013.

  1. Le 901 New Member

    Le 901
    I can find no discussion on any threads and I have an over gassing problem. I'm not going into great detail unless its ok to bring up the subject.
     
  2. Zak Smith Operations

    • Instructor
    Zak Smith
    Hi,

    Not at all. What we have found is that AR type rifles that are properly set up to begin with generally do not need adjustment to work properly with a suppressor mounted. However, due to the range of AR's out there, there are some that are set up with too much gas to begin with and this is exacerbated by suppressor use. There are several ways to fix the fundamental problem, and there are a couple ways to fix the symptoms.
     
  3. Le 901 New Member

    Le 901
    I was reading some comments in another forum about my over gassing problem and someone made the comment that I was using a can that was designed for a bolt gun and not a semi-auto and the person he was talking to agreed and responded that he wasn't going to open that can of worms.

    I have read a lot and talked to a lot of manufacturers and not one time have I ever heard of a difference in semi vs bolt as far as suppressors go. I have spoken to y'all numerous times about my over gassing problem and I guess my question is....are suppressors designed for either bolt or semi-auto guns ?

    Mine is a 30p-1
     
  4. Zak Smith Operations

    • Instructor
    Zak Smith
    AR-10 pattern rifles are notoriously over gassed without a suppressor. I once had an Armalite AR-10 that had been built by JP Enterprises. It had an adjustable gas block that was comprised of a set screw that reduced the aperture through which the gas flowed in the gas block itself. I was shooting a 3Gun stage at Pueblo West and all of a sudden my rifle started not "quite" returning to battery. A mild hit on the forward assist (had it had one) would have been enough to get the rifle back into battery. After I finished the stage I noticed the set screw was missing. So in summary, with the gas venting directly to the atmosphere, the rest of it that stayed flowing through the gas block & tube was enough to cycle the action 99% of the way.

    That said, a rifle that is properly set up with the right amount of gas, in our experience, will operate just fine with our suppressor mounted. We know of a bunch of OBR's using our suppressor and they work fine.

    The one thing you can do in terms of design is to try to reduce the backpressure; however, this is usually a tradeoff with suppressor and first round pop (FRP).

    hope this helps
    Zak
     
  5. Le 901 New Member

    Le 901
    I was advised to get an adjustable gas block to help with my problem, however that has been a problem all by itself. The gas block that I tried would not make any difference in the amount of gas that was being returned to the bolt, it wouldn't even shut completely off even though I was told it would do so. I' don't understand why I can put a 223p on my Colt Sporter 2 which is direct impingement, and have no issues whatsoever. I put the 30p-1 on my direct impingement Colt LE 901 .308 and now have an unreliable gun that at times will pull part of the rim off or if it does pull the spent round out it will get stuck in the ejection port while trying to feed another round underneath it. So I end up with one partially fed and at the same time a spent one partially ejected which also prevents me from dropping the mag since the round is partially in the chamber but has not cleared the mag.
     
  6. Zak Smith Operations

    • Instructor
    Zak Smith
    It sounds like the design of the gun is screwed up, or your particular specimen is screwed up. In my opinion, a shorter-than-rifle-length gas system in a direct impingement AR-10 pattern rifle is to short. Think about it this way, if the rifle is so close in its operating range to failure that a small change (add suppressor) can cause it to fail, what other changes due to ammo, etc, may also make it fail? It's certainly possible to make an AR pattern rifle "work", but have it be operating with much, much less margin in one or more directions to failure. From what you've said this is the case for your rifle.

    What gas block did you try?

    Also, what ammunition are you using?
     
  7. Le 901 New Member

    Le 901
    The gas block I tried was a Syrac adjustable. I spoke to Jason Adams at length about this problem and he assured me his block would shut off completely making me have to manually operate the charging handle. Well it did not shut off and I could tell no difference whether it was wide open or fully closed and he stopped answering my calls or emails. I talked to Chris at Noveske and he said their switch blocks were mated to their barrels. I finally got a block from SLR Rifleworks which does adjust all the way off. The ammo has ranged from Federal Gold Medal match 168 gr, Hornady TAP, CBC, South African battle packs and any other commercially made ammo.
     
  8. Le 901 New Member

    Le 901
    What got to me was that someone said (on a forum) they had just got their tax stamp and put an AAC sdn 6 on their le901 went out and fired approx 60 rounds thru it with no problems and that the guy with the problems (me) was using a suppressor for a bolt gun. He said the reason I was having problems (and another person also agreed) that the problem was that the can was for a bolt gun and not a semi auto.
     
  9. Zak Smith Operations

    • Instructor
    Zak Smith
    Well, the 30P-1 and 30BA were designed originally around bolt gun applications and that basically means we did not go out of our way to further reduce backpressure. However, we have a large number of customers who use the 30P-1 or 30BA on semi-auto rifles of the AR pattern with no problems.

    My take is that your rifle either categorically or maybe just that one specimen is operating too close to the line of "not working" if a small change in residual muzzle pressure after the bullet leaves the barrel makes it not work. If we have ArmaLites, JP's, GAP's, and OBR's working just fine and the odd one out is the Colt, that is a pretty clear indication they are doing something different and wrong.

    So with the new SLR gas block that you can turn off, what happens as you dial down the gas amount?
     
  10. Le 901 New Member

    Le 901
    It did shut the gas off completely which made me have to operate the bolt manually. I opened it up a few clicks at a time until it started working properly. Then I ran a full mag (20rds) through it and it worked flawlessly. I'm happy at this point but it was time to go so I started packing up to leave. When I went to pick up my gun it broke open like an over/under shotgun. I thought that I had forgotten to push the rear pin in that would lock the receiver. Upon closer inspection the pin was in place but the lug from the upper receiver was still in the lower receiver. It had broken loose from the upper receiver. So now I have a broken gun.
     
  11. Gungho03 New Member

    Gungho03
    Le 901, I'm on the edge of my seat. How does the story end? "gun broke", Colt fixes? ????
    I have an 30P, and was, key word was interested in the Colt LE901.
     
    Le 901 likes this.
  12. Le 901 New Member

    Le 901
    It's kinda long story, I'm at work but fixin to go home. I'll respond tomorrow cause I'm tired. Been here since 6:30a
     
  13. Le 901 New Member

    Le 901
    Sorry it took so long to reply, but Colt had the gun for about 9 months as there are no parts available for repairs. I had to wait until they started production again and they could take an upper receiver off the line and use it on my gun. Since this is a modular gun anything that happens to the upper will require a new upper assembly. There are no short barrels available and no plans per Colt as this would require another upper assm. Yes, they fixed it at no charge to me, somehow the fun is just not there anymore as I am continuesly worried about shooting it.
     

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