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Posted: 4/22/2006 3:49:43 PM EDT
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Hello I finished my pistol build today and i went out to my back yard and load a mag into my new baby and i pulled the charging handle and chamber a round and fired but it didn't eject the shell and didn't chamber another round. I have a pig tail gas tube because I heard of people not having enough gas to cycle. What's wrong with my new AR?? thank you |
Next is to verify that the gas block hole is lined up w/ the gas hole in barrel. Was the block on the barrel when the unit was given to you or did you have to mount the gas block? Does the carrier/bolt assembly even move back at all? What recoil system do you have? If it's the M1S type, ya never know if the spring is too strong (odd, but could happen)..... If it's the CAR type, then it shouldn't be an issue. |
Simple test to see if the hole is lined up. Get a can of spray cleaner (Gun Scrub, etc) and spray down the gas tube. It "should" dribble in to the barrel. Next would be to remove the gas block and see how big the hole is. Not sure the type of gas block you have.... so it could be easy or hard. Edit- Another "idea". Go fire a few different types of ammo, say just one round of each. Examin the brass for any scratches. Make note where the extractor is though. If you notice a scratch on the brass, it is possible you might have a burr that is just big enough that when the case fires and expands, it is holding it in.... just another thought.... |
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Hello Yes the hole lines up i sprayed some clp down the tube and it came out the barrel. I removed the front sight and the gas hole is very small and the gas hole on the front sight is way bigger.The shell comes all the way out of the barrel but it gets stuck somewhere on the face of the barrel. thanks |
Hummmmm........ sounds like it's short stroking for sure. Doesn't sound like it's getting hung up in the chamber. Next, get some drills bits and find which drill bit fits the gas hole exactly. Or one that is 'close' (as in, XX size fit's, but loose, but the next one up, XX, is too big). That way the gas experts know how big your gas hole in the barrel is. The 'very small' doesn't say anything..... Slowly but surely the 'hive mind' will get this solved. 
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No problem. Unfortunatley, my suggestions end here. I have no idea how big a gas tube hole should be in a barrel. Other people probably know.....so I hope someone chimes in. Well, I lied.... the next step, would be to drill the hole "larger". Personally, I'd like to know if your size is big or small with what is considered "standard". Some say do the trial and error method. As in choose the next sized bit (assuming it's not a BIG jump) and drill the hole bigger and then shoot it to see if it cycles. If it doesn't, go next size and so on..... That's what I think I've read before on other posts. But I'd personally like to know if first if the .081" is normal, small or big. Okay gas system expters..... how's that hole size compare????? Come on...... 
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I'll chime in. Your next step (should have been your first) would be to verify that your gas rings on your bolt carrier are not lined up. If they are, stagger them. If you have a McFarland one-piece gas ring, you might consider replacing it with standard rings which fit tighter. Next step (if this doesn't work) would be to check your gas key and see that the two bolts are properly torqued and staked and that the carrier key fits flush against the carrier. This is important as any burrs, imperfections, etc on the key or on the carrier can cause a gap and the gas will escape there. Next, check to see that your gas tube is long enough. Check protrusion into the receiver and relate it to a proper AR Rifle. It's possible that the tube is too short. May I ask you to expand on the malfunction? Is it short-stroking... that is it actually pushes the bolt carrier back some, but not far enough? The way to test this is to close the ejection port cover. When you fire the gun, the movement of the carrier would pop the door open. If it doesn't, you're not getting any gas to your bolt carrier. Beyond this, I would check to see that your bolt carrier isn't hanging up on something. Your buffer retaining pin/spring for instance. Perhaps you've got the bolt installed backwards (hey, it can happen if you mix and match parts or if you accidentally got a lefty bolt). If your bolt carrier is moving, are you shooting Wolff ammo? Steel cases get stuck in chambers. It's also possible your chamber is rough. Hope this gives you enough to go on. |
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What buffer are you using in your car buffer tube? I had to take an "H" buffer out of my AR pistol. It did cycle, but the brass was just dribbling out of the ejection port. Maybe your buffer is a little too heavy also. After changing to the cheap, lightweight buffer, the brass flies out of the pistol pretty good now. |
Here's the series needed when retuning my Bushmaster from the original too small 0.0700 sized port. #50 0.0700 #49 0.0730 #48 0.0760 5/64 0.0781 #47 0.0785 #46 0.0810 #45 0.0820 #44 0.0860 #43 0.0890 #42 0.0935 3/32 0.0937 FWIW, I stopped at the #43 on my Bushmaster 10 incher, and it locks back empty 100% with a standard carbine buffer and bare muzzle. I inserted a section of cleaning rod into the bore so when the drill would break thru I would not go too deep and hit the far side of the bore. The SHARP bits cut like butter, and NO DETECTABLE BURR was present afterwards. The hardest part of retuning the gas port was removing the gas block taper pins. HTH. Paladin |
It is all condensed in a single area, it's called the troubleshooting forum. There you will find troubleshooting sequences. The hard part is getting people to understand what their actual failure is so they can follow the proper procedure. I did a write-up on how it works that would be helpful if you look at the problem with a full understanding of the theory. My article is tacked in the troubleshooting forum. |
Ah..... 
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