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Posted: 1/19/2009 12:27:26 PM EDT
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I went to the range today and shot a mixed bag of Wolf, Prvi and Federal. In all, I shot about 260 rounds. With all 3 types, I was getting groups of about 1"-2" shooting off hand at 50 yards. However, the bolt only locked back 2 or 3 times. It locked back once with the brass and twice with the Wolf. They also locked back with different mags.
The gas rings were offset, each mag locked back at least once (I was using 3 pmags) and locked with both the brass and Wolf. What would be causing this? I've had it repaired once for FTE's but since getting it back its run flawlessly except for the bolt catch. The bolt catch also moves freely. |
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So the bolt is not locking back all the time when the last round has been fired?
Sounds as if it's short stroking. Do the short stroke test. From the troubleshooting sticky at the top of the page: "––-TEST FIRING PROCEDURE––- -Unload the rifle and verify that it is clear. -Check the bore for obstructions. -Load the rifle with one round from the magazine. Use quality ammunition and a proven magazine for this. -Aim downrange and fire, the bolt should catch on the bolt stop. Hold the rifle as loose as possible. -Reload and repeat the process if the rifle does not lock open Depress the bottom of the bolt stop before firing this time. This allows for weak magazine springs, sticky followers, or an overly strong bolt catch spring. -If the bolt does not lock open then there is a gas system problem. Investigate and repair the problem. -If it only locks open with the bolt stop depressed, repeat the process with a different magazine. If the rifle still fails to function then look at the bolt stop as a probable culprit." Also don't get to hung up on the gas rings being lined up. In a properly functioning AR, having the gas rings lined up will NOT cause any problems. |
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If I shoot tight (holding the lower near the magwell BUT NOT TOUCHING THE MAG) or shoot off of sandbags, it will fail to lock back. If I hold the foregrip which forces me to stretch out and hold it looser, it'll lock fine.
It would seem to me that it is cycling too fast if it'll fail to lock when the rifle takes 100% of the recoil but locks fine when I recoil with the rifle. |
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