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Posted: 8/14/2009 9:50:19 PM EDT
| I built an upper with a 18.5" barrel and intermediate gas tube ( 2" longer than a middy i think) and I'm having issues with it cycling. The complete lower I'm using on it was off a 14.5" carbine gas system (DI). I need advice on what else to troubleshoot. I know its short stroking because when firing the last round in a magazine it wont lock the bolt open, it ejects fine. It does cycle sometimes and when it does, its for only three consecutive shots at most. Then it goes back to not cycling for a while then it may work a few shot later(pulling the charging handle each time). I had some issues with bent gas rings and the bolt was really tight fitting in my chamber, I measure the seven bars (excuse my lack of better terms) around the bolt and found them to be two-three thousandths of an inch longer than my identical working RRA BCG on another complete rifle. I ground them down to the size of my other one with a dremel tool, it is no longer hard to fit in the chamber. Do i need a different buffer spring since the complete lower is no longer on a carbine but on a intermediate gas system? also i hear alot about buffer weights but not sure about them, do i need to try a different one? thanks in advance for your help. i will try to answer questions as best as i can. |
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Couple of things. Make sure the gas block is center over the port in the barrel. If it is off front to back or side to side it can limit the amount of gas getting to the action.
Make sure the carrier isn't rubbing on the gas tube. On the bolt, did you grind the front or the back of the lugs? If you ground the back your headspace may be too long...I'd invest in go/no-go gauges and check it out. The gas pressure is much higher in the shorter gas systems, so you most likely will need a lighter buffer. As always, use good ammo. |
| Because you stated you have an intermediate gas system I will assume this is a Noveske barreled upper. My Noveske barreled SPR was having similar problems cycling. It would fire a round and eject the case but not chamber a new round. I changed the ammo I was breaking it in with and now its GTG. Try some "hotter" ammo. Good luck |
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Quoted: Discard the bolt you ground and replace it with a new one. Check your gas port alignment. Try good 5.56 ammo, like Winchester Q3131, Prvi M193 or Federal XM193. Before you throw away the bolt you just ruined, take out the extractor and ejector as spares, then throw it away. |
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Quoted:
Because you stated you have an intermediate gas system I will assume this is a Noveske barreled upper. My Noveske barreled SPR was having similar problems cycling. It would fire a round and eject the case but not chamber a new round. I changed the ammo I was breaking it in with and now its GTG. Try some "hotter" ammo. Good luck this |
| How is the bolt ruined if it matches the length on the other lugs on my working bcg? To answer the question I ground the back of the lugs. I was gonna pitch to bolt anyways so I thought I'd give that a try. ( I noticed that pkfirearms was selling their noveskr barrels with a bolt so I was gonna try to find one.) I'm using black hills 55gr soft point, Winchester varmint 40 gr, umc 55 fmj,and reloads with 55grain vmax. Still same failure with all types. Could gas rings have anything to do with this? Or just the buffer spring? |
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Quoted:
Because you stated you have an intermediate gas system I will assume this is a Noveske barreled upper. My Noveske barreled SPR was having similar problems cycling. It would fire a round and eject the case but not chamber a new round. I changed the ammo I was breaking it in with and now its GTG. Try some "hotter" ammo. Good luck What ammo are you using so I can give it a run |
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it seems like you have the worst luck ever. bad bolt/gas rings, function issues, broken DD lite rail, etc... what ever happened to the Daniel Defense lite rail that you had that was broken. i'm sure DD has sent you a new one by now. was there an explanation of what went wrong? |
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Quoted:
it seems like you have the worst luck ever. bad bolt/gas rings, function issues, broken DD lite rail, etc... what ever happened to the Daniel Defense lite rail that you had that was broken. i'm sure DD has sent you a new one by now. was there an explanation of what went wrong? Yeah I had terrible luck with it. I know alot of it was being a newb and I had to go through alot of trial and error. I may break it down and trade it as is. I have a upper I ordered from rra way back last year that's coming in soon. Daniel defense was badass they sent me a new replacemnt rail. They said they didn't care what I did to it, it shouldn't have broke. I got the new one in about two weeks after shipping it to them. I was very impressed with Daniel defense |
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