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Posted: 5/14/2013 11:05:55 PM EDT
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I was trying to zero my scope on my new pistol build and I ran into a problem. It will only fire one shot at a time and it won’t eject the spent casing. I am using Lake City Ammunition 5.56x45mm NATO 62 Grain XM855.
What can be the cause of this? I am new to pistols. Does it just need a different weight buffer? What is a good one to try? I wanted the JP silent buffer but I don’t know now I am having this problem. I will be going back to range in two weeks. 
Innovative Arms WAR Upper Reciever Centurion Arms Cold Hammer Forged (CHF) Barrel 11.5 Inches Carbine Length Gas Centurion Arms C4 Rail 9" Rainier Arms Raptor Charging Handle Fail Zero BCG Noveske Krink KX3 Flash Suppressor Phase 5 Tactical™ AR-15 Pistol Buffer Tube Complete Assembly. Buffer tube, Spring, Carbine Buffer. |
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Quoted:
Does your extractor have the o ring on the spring? If not try that or a heavier extractor spring. I'm not sure if FTE is entirely buffer related but I am sure someone more knowledgeable will provide a solution to the problem. Yes the extractor has the o ring. I just ordered another one from bravo company just to make sure nothing is wrong with the current one. |
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Your buffer, carrier and spring do not have enough mass or tension to allow for the case enough time to contract from the chamber walls. So the carrier is trying to extract a case while it's pinned in the chamber by pressure. So what happens, the extractor pulls over the rim and it doesn't extract. More mass will allow that microsecond more for the case to loose pressure and tension against the chamber wall and allow it to be extracted.
M16 carrier, H2 buffer and a heavier carbine spring will help with your problem. |
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I would also have someone else shoot your pistol so that you can observe what's actually happening. Is the bolt not going far enough reward to eject or is the extractor not doing it's job? Then I think you can asses better what needs to be done. I've never had a problem with an extractor, but I have had problems with springs being to strong and buffers being too light. I once cut a few spring loops to a spring I was using in a pistol I built....fixed the problem and never had an issue with the pistol again. Not sure that is the case here, but again...I think you could make a better assessment after observing what is going on.
Good luck! |
| My RRA 10.5" build wasn't extracting the spent round, and was trying to feed the next round at the same time. It would only do this unsuppressed though. With the suppressor it would function ok, but ejection was erratic, and it wouldn't always lock back on the last round. I took it in and had the gas port opened up, now it functions perfectly unsuppressed, but it's cycling way too fast with the can on. It ejects the spent round, but only lets the fresh round get half way into the chamber before it dents the casing. I'm using a standard carbine buffer now, going to try something heavier this weekend, probably the H2 mentioned above. So long story short, I had to have my gas port opened to function normally unsuppressed, now I need a heavier buffer to slow it down a bit suppressed. |
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Quoted:
Does it lock back after firing that one round ? I'd also check the gas system, gas block on right, gas tube right length and gas key tight. I think I am an Idiot. I had it in a gun stand to start. I think it was cycling fine just not picking up the next round in the mag. I was using gen 3 20 round PMags. This might have been an issue with the Gen 3 PMags. I heard they have a few issues with different lowers and not locking all the way in correctly due to the tab on the side. Then when I was shooting off hand not sure how to hold a AR15 pistol I just had the pistol stock out in the air since there is not much recoil anyways. I never put it in my shoulder. I watched a few YouTube videos and it looks like you are suppose to put the buffer tube area in your shoulder just like a stock? I am going back the range in a week and a half. I will put the new extractor in it and take a few extra buffers. And shoot it correctly. |
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There are three(3) positions that most people utilize when shooting an AR pistol. 1) Cheek weld on the pistol tube. The primary reason for the foam rubber on the tube. 2) Single point sling with pistol fully extended and the sling taunt, stabilizing the pistol with a two point grip. 3) Shouldering the pistol tube but this will be uncomfortable since the system is not designed to be operated in this manner(it's a pistol not an SBR). IMO shooting an AR pistol is unlike shooting any other type of firearm and like anything else proficiency will only be achieved with practice.
Here's a video showing what I think is probably the most practical way to shoot an AR pistol: http://www.youtube.com/watch?v=o9VLQWJZh44 |
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Quoted:
There are three(3) positions that most people utilize when shooting an AR pistol. 1) Cheek weld on the pistol tube. The primary reason for the foam rubber on the tube. 2) Single point sling with pistol fully extended and the sling taunt, stabilizing the pistol with a two point grip. 3) Shouldering the pistol tube but this will be uncomfortable since the system is not designed to be operated in this manner(it's a pistol not an SBR). IMO shooting an AR pistol is unlike shooting any other type of firearm and like anything else proficiency will only be achieved with practice. Here's a video showing what I think is probably the most practical way to shoot an AR pistol: http://www.youtube.com/watch?v=o9VLQWJZh44 Could not having a good stance cause it to malfunction? Like limp wristing a hand gun? |
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Back to basics, does it lock back with the last round fired from a mag every time? The answer to this directs us what next to inspect.
Off hand it sounds like you have a gas issue or possibly but less likely a mag issue. It is always nice to try several different types of mags when test firing. |
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Quoted:
Back to basics, does it lock back with the last round fired from a mag every time? The answer to this directs us what next to inspect. Off hand it sounds like you have a gas issue or possibly but less likely a mag issue. It is always nice to try several different types of mags when test firing. Ok I went back to the range today. I took a few buffers and a few different mags and two different bolt carrier groups. First off buffers. Spikes t2 buffer The buffer that come with the phase 5 pistol stock. Buffer out of my other rifle. None of these made any difference. It would eject the round but would not go back far enough to pick up the next round. Next bolt carrier groups. Core15 fail zero bolt carrier group Jp bolt carrier with fail zero bolt. The core15 would eject the round but not pick up the next. The JP would not eject the round at all. From watching the rifle cycle it looks like it is just not going far enough back. A guy at the range suggested either cutting some of the coils off the buffer spring or wait till I get the sbr and suppressor papers back in 5 months. He said it will most likely cycle with the carbine gas system with the suppressor. So carbine gas is not used for pistol builds? Lastly I guess my lower does not like gen 3 PMAGs. It would not pick up a round using the gen 3 20 round mags when I let the bolt slam forward after putting the mag in. Any idea on how to fix this? It works perfectly with the gen 2 30 round PMAGs other than not going far enough back to pick up the next round. |
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Here's a good video demonstrating the three pistol shooting techniques:
http://www.youtube.com/watch?v=TS4wJqKUmQ4 The technique used has nothing to do with reliability in a gas operated firearm, though it's a good idea to experiment to find what works best for you. My build beat me up when shouldering until I went with an H3 buffer which smoothed it out considerably. Mine had the opposite problem. It was beating up brass, launching it like an AK, and the recoil was a bit excessive for an AR. |
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Quoted:
Back to basics, does it lock back with the last round fired from a mag every time? The answer to this directs us what next to inspect. Off hand it sounds like you have a gas issue or possibly but less likely a mag issue. It is always nice to try several different types of mags when test firing. Well, did it (bcg) ever lock back on a single round fired? |
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