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Posted: 1/6/2006 4:12:03 PM EDT
Hey guys, I'm hoping yall can help me out. I have a post ban m4gery upper that I think is getting way too much gas. If I try to run with the standard CAR or "H" buffer, I get ftextract. The extractor will jump right over the rim (yes I've tried the 0-rings, wolff springs, and other extractor aids and changed extractors). I'm currently running a solid 9mm buffer, and it has cured my jams, for now. I'm assuming that it slowed it down cycling enough to let the case contract after firing, thus allowing it to extract. Have I diagnosed correctly? I've not had any jams since going to the 9mm buffer, but I'm getting a lot of wear at the base of my shell deflector, and the ejection pattern is eratic. It busted gas rings after one or two shots before the 9mm buffer, but now is much easier on them. Recoil also feels clunkier than with other AR's I've fired. If so, what is the best long term solution to this problem. The barrel is still very accurate, so I hope I don't have to replace it. I've seen services where the gas port is plugged and re-bored. Is this a good idea? If not, what are my options? Has anyone else had this problem, and found a cure? Will this cause premature wear, or am I worried about nothing and should just shoot the devil out of it. It's my patrol rifle, and I really want the utmost in reliability. Thanks.
Link Posted: 1/6/2006 7:00:52 PM EDT
Link Posted: 1/6/2006 7:26:00 PM EDT
Action spring comes out right at 10.75 incnes, nad I haven't noticed any strange marks on the brass. I'll have to pick up something tommarrow to mic the port and id of the tube. I'll have to get the headspace checked Monday. Thanks for pointing me in the right direction. I'll let yall know how it comes out.
Link Posted: 1/7/2006 9:41:02 AM EDT

Originally Posted By georgiaboy:
Hey guys, I'm hoping yall can help me out. I have a post ban m4gery upper that I think is getting way too much gas. If I try to run with the standard CAR or "H" buffer, I get ftextract. The extractor will jump right over the rim (yes I've tried the 0-rings, wolff springs, and other extractor aids and changed extractors). I'm currently running a solid 9mm buffer, and it has cured my jams, for now. I'm assuming that it slowed it down cycling enough to let the case contract after firing, thus allowing it to extract. Have I diagnosed correctly? I've not had any jams since going to the 9mm buffer, but I'm getting a lot of wear at the base of my shell deflector, and the ejection pattern is eratic. It busted gas rings after one or two shots before the 9mm buffer, but now is much easier on them. Recoil also feels clunkier than with other AR's I've fired. If so, what is the best long term solution to this problem. The barrel is still very accurate, so I hope I don't have to replace it. I've seen services where the gas port is plugged and re-bored. Is this a good idea? If not, what are my options? Has anyone else had this problem, and found a cure? Will this cause premature wear, or am I worried about nothing and should just shoot the devil out of it. It's my patrol rifle, and I really want the utmost in reliability. Thanks.

who's the manuf. of the firearm ?
Link Posted: 1/7/2006 2:30:58 PM EDT
Link Posted: 1/8/2006 9:45:25 PM EDT
The upper is a rock river flat top that I've put on a grizzly lower with bushmaster LPK. I will be doing some shooting tommarrow afternoon. I'll double check my brass, and let you know on the extractor marks. thanks guys for all the help.
Link Posted: 1/9/2006 6:57:24 PM EDT
[Last Edit: 1/9/2006 6:58:28 PM EDT by georgiaboy]
Did a little shooting today. The extractor is leaving a compressed mark on the rim. I can see a distinct mark where the extractor rides, and it appears to be compressed about a third of the thickness of the rim. reliability was fine, and ejection was to about 1 o'clock. I'm posting a pic of my shell deflector. if you look at the base, you can see where the anodizing has worn through and is now bare metal.



Once again, thanks for the help.


P.S. sorry about the pic quality
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