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Posted: 3/18/2012 2:53:24 PM EDT
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I'm getting to the next stage of "testing" a new build. I've got it now functioning well with all types of ammunition and now have ejection questions.
I tried swapping bolts and carriers but got them confused as to which one was doing what pattern. One carrier had extremely loose gas rings, the bolt would not even stay locked in the upper if you had the dust cover open and the charging handle wasn't latched. This one had the O-ring upgrade. The other carrier had good gas rings but lacked the O-ring. Both carriers had maybe 200 rounds through them. One carrier and bolt had a nice 5 O-clock ejection pattern several feet away. The other carrier had a weak ejection pattern at maybe 2 O-clock. Barely clearing the bench. I've since added the O-ring to the second carrier and found a good gas ring to tighten up the first carrier. Are any of these symptoms related to the issues I found post tear down or do I need to look closer at the ejector springs? |
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Gas rings and extractor O rings are two different subjects.
To test gas rings, push the bolt all the way into the carrier, then aim the bolt face straight down. If the bolt moves downward to the unlocked position, the gas rings are toasted. Extractor spring tension, if the spent case is not dropped from the bolt face as the bolt goes to pull the spent case out of the chamber and the bolt begins to reach it more reward position, then the extractor and tension are correct. If the extractor slips off the the spent rim case when the bolt is pulling the spent case out of the chamber/on the way back, you have other problems (weak extractor spring, worm claw on the extractor, chamber fouled or rough, barrel gas port too large and you have over function, or even a worn out hammer or recoil spring), but adding tension to the extractor spring will help band-aid the problem. And regarding the B/C in the upper, with the upper shotgunned opened and the muzzle pointed downward , the B/C should free run from being pulled all the way back against the charging handle, down to locking up the bolt when you release the B/C. |
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Dano,
That's just my problem. I tried the gas ring test and it failed on one bolt. Only had one spare ring and installed one good one on the bolt. For now it passes the gas ring test. Basically I have one bolt that ejects at 2 o clock and one that ejects properly, I was wondering if any of my symptoms could be traced to extractor tension or gas rings. Both of my extractors are functioning, I am starting to wonder if I have ejector problems. |
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Rearsprocket,
That is the kind of thing I was looking for. I have purchased a spikes T3 buffer that is about two ounces heavier than stock. I'm hoping that will do the trick. I've also rebuilt the gas rings from my other bolt. Next time at the range will tell me the whole story. |
| The one shooting at 5:00 would be the one leaking gas and a heavier buffer will make it worse. The one at 2:00 will benifit from a slightly heavier buffer H1 or H2. The buffer weight your running now wasn't stated? You are much better off using Colt buffers like the H1, H2, or H3. Also when adjusting buffer weights you should go in steps and not just jump to the heaviest. There are multiple reasons for short stroking like stated above, make sure the gas system is clear and in alignment and check for friction or hangup with BCG cycling. Good luck. |
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Rearsprocket,
I currently am running a Spike's T3 buffer in both carbines. I have a standard buffer laying around somewhere and another one where I had a brass weight to replace the steel weights. The brass weight one weighs slightly more than a Spike's T1 buffer. The reason I went with T3 is because I can open it up and replace steel versus tungsten and make T1, T2, or T3 where Spike's T1 and T2 is a tungsten powder mixture. I'm going under the assumption that H1 versus T1 is about the same weight and so forth. My original problem was I couldn't eject steel cases after about a mag. From that point I polished the chambers with flitz and at the same time put in a T3 buffer. I say one of them ejects at 5:00 but in reality it ejects rearward several feet back. The one I was really concerned with was the one that ejected about 2:00 with barely any force. My next outing will have two good bolts, and several weight buffers to "tune" or "test" all available combinations. Currently both carbines run fine on 6+ 30 round mags and no FTE. Just trying to get what I feel should be a reasonable ejection distance (IE not a weak ejection). |
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