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Posted: 11/17/2004 5:32:29 PM EDT
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I have an RRA varmint upper with 18" SS barrel. The lower is an Ameetec with an RRA LPK and an RRA 2-stage trigger. The rifle has had about 300-400 rounds through it. I load a Bushmaster 10-round magazine with 5 rounds and insert the magazine. Pull back the charging handle and let fly. The top round chambers, I pull the trigger and hear the hammer fall There is no bang and the charging handle needs to be tapped to get the bolt open. Typically there is no firing pin mark on the round. If I remove the rounds from the magazine, reinsert the magazine and manually load the round into the chamber and then hold down the bolt release the round will fire. The bolt locks open. As long as I manually load the rifle fires with no problem. It does this with both of the Bushmaster mags. 'What I have not tried so far is to manually load the first round and then put a loaded mag into the rifle. Any ideas? |
That is what appears to happen. Now I need to find out why. It only happens when I try to fire from these magazines since the bolt closes properly when I single feed. These magazines have been used for several hundred rounds in t wo different rifles with no problems. I have a number of 30 round magazines which I will try and I will also try single loading thee first round and then inserting the magazine with 4 rounds in it before firing to see if this is a first round problem. |
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Ernief You didn't say what type of ammo your using but when I've encountered this happing its usually been a reloaded ammo. Most std full length reloading dies do not go down far enough on the cartridge case to fully rezise the web area [ area right before the extractor groove] leaving it oversized.On a bolt action rifle this is not a problem due to the manual caming action of the bolt. On semi and full auto you do not get enough force to seat the round fully in the chamber. This usually is more of of a problem with military brass as they have a thicker web than commercial brass. If you are loading your own get a small base full lenthg reloading die. Size your brass with the standard die and then run them threw the small base die and proceed as normal. This should fix your problem. If your using good commercial nonreloaded ammo and your still having this problem I would say you have a slightly undersized chamber and either return the barrel to be fixed or have a gunsmith run a finish reamer in it to bring it to spec.  PS i've encountered this with some commercial reloaded ammo too. |
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