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Posted: 12/27/2005 3:28:00 PM EDT
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Armalite M15. Same mags/ammo. Shot 100 rounds without problem. Reloaded mags and started to shoot again. 10 rounds into 2nd shooting period and Bolt rode over cartridge and jammed half way down. Cleared weapon. Field stripped and found no problems. Everything nice and tight, no excessive build up, etc. Started to shoot again (no boing from buffer) and no problem until I noticed my hold against my body loosened. Then jam occurred again with loose hold. Cleared weapon. Tight hold and no further jams. Unusual situation? TIA |
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From your what you described, it sounds like you had a bolt-over-base failure, which is usually caused by a weak magazine spring. Rebuild/replace magazine and you should be good to go. If the magazine is new, its possible its out of spec. I have two brand new Bushmaster magazines which are out of spec and will not work reliably. They look good and make excellent book ends. If it is the magazine, which I am guessing it is, make sure to quarantine it from the good ones. |
you'd think that but it's not true, even a gas op system needs resistance, that's why the 6,000 round endurance test requires "unrestrained" firing at certain intervals, it's a VERY good test of the strength of the recoil. CAUTION war story time I had a LE gal bring me her duty rifle (BFI carbine) one night, said it was FtF, FtEj intermittently. I tore it down, checked every part inspected her mags (USGI) and ammo (Black Hills blue, issued) found no defs except the poor key stakes. next day took it to the range, loaded it up and short stroke tested it ten times, good to go on each one, put a mag and a half through it from the shoulder as fast as it would run, no malfs. Handed it to her, her first round FtF, then sporadic FtF and FtEj from there on for the rest of the mag. I short stroke tested it "unrestrained" and it failed every time. We narrowed it down to the gas port by parts swapping, knew it was smaller than normal from previous inspection but wanted to check all the other variables first. Opened the port up to standard size and it ran like a top once I whacked the FSB over to TDC. This is how we test clones now   short stroke test it
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I am 6'3" and 255 lbs. So hope stature doesn't have anything to do with ithanksWill continue to shoot, inspect and troubleshoot if needed. BTW: Same ammo and mags used in shoot of NIB Colt LE6920, right out of the box , and no malfunctions. Not looking to start manufacturer vs manufacturer thread/war! (already read the list the best manufacturer opinion thread) Tweak:When you talk about swapping parts where they from same model and manufacturer? |
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Thanks but that is why I have the AC556, Swedish K, MAC M11/9 and .380 (carried in shoulder rig). he And the technique is much easier to master. Flip selector (except the Swedish K) pull trigger once. But I am trying to master the ARs. |
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Factory buffer and will keep your suggestion in mind. Back to the range Jan.2nd and will run the one that seems to give most problem and all my others. Will also use in the Colt and see if it will reproduce problem in the Colt. (which did not happen last weekend) |
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