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Posted: 1/30/2017 3:34:14 PM EDT
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I took HD gun out this weekend to run some rounds through it. This is a ~6 year old gun that has several thousand rounds through it. CMMG upper, carbine gas system, 5.56 chamber, BMC BCG, standard weight buffer and spring.
Ammo was PMC bronze and wolf gold. After the first couple of mags I started to have failures to eject. the extractor would pull the case out the bolt would strip the next round out of the magazine, however the fired case would end up sticking out of the ejection port at 90 degrees, trapped between bolt face and the edge of the ejection port. 1-2 rounds out of a 30 round mag Swapped ammo same issue swapped mags same issue Swapped BCG from rifle with issues to another rifle. the problem did not follow the BGG, as in the rifle with failures continued to have them and the other rifle with the BCG from the failing rifle functioned fine. Checked for gas leaks did not see any sign of a leak Brass that was ejecting, was at around 2 o'clock (so maybe slightly over gassed like most carbine length gas systems) Checked the buffer, and buffer spring to make sure it was not bound up. Rifle was clean when the shooting started. Any suggestions as what to look at next? |
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Low gas pressure to BCG for some reason. Maybe loose gas block or obstruction of gas flow at the port or in the gas tube?
Or perhaps the opposite issue of cycling too fast and bolt trying to close before ejection is complete. That might suggest a weakened buffer spring over time and round count. |
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Think I found the problem, the roll pin on the buffer that hold in the rubber/plastic end piece had come out one side and was catching the spring. It was also allowing the rubber/plastic end piece to move around and get all chewed up.
Have to wait until the weekend to test. |
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