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Posted: 3/22/2010 5:14:12 PM EDT
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Went to the range the other day and shot several different types of ammos.
No problem with armscor and aguila ammo. Short stroking problems with PMC, UMC, and some brass surplus. It is a bushmaster m4 style upper with atleast 2500 rounds through it. It has been shooting everything I put in it until the last trip. I did have short stroking problems with it when I first got it but it was due to the buffer spring. I have shot alot of PMC in the past with no problems. I just installed a spikes buffer before the trip to the range. It fired the armscor and aguila just fine. It short stroked with the PMC so I swapped the buffer to the H buffer, it still did not work so I tried the standard carbine buffer and still short stroking. Bolt was not locking back on last round and was not stripping a new round after it was fired. I shot the armscor again with all 3 buffers and had no prolems. I checked the gas key and it is properly staked and tight. I replaced the gas tube but it looked fine. The gas rings feel a little tight so they are definately not loose and they have never been replaced. The bcg is a LMT. Not sure what's going on. Any ideas? |
| I had this kind of problem once. checked all moving mechanisms and mags. everything looked fine. then checked the throat inside the chamber and it was filthy dirty even after I thought it had a good scrubbing. If you have a little dirty throat, good polished ammo will still run fine in it, but ok-good brass will stick a little inside chamber walls then short stroke. You might also want to inspect the empty cases and compare them to the good cases that ran fine. So if I was you, I'd check the chamber and throat to see for gunk w/ a bore light. The ar15 chamber brush don't quite get to the throat's area when cleaning, so I use a .357 copper brush for throat and .410 brush for chamber cleaning. mine ran like a champ again. hope you get it working again. |
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