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Posted: 8/13/2011 6:29:01 AM EDT
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I've put together a 5.45 x 39mm Adams Arms Piston Upper, and a Smith and Wesson M&P15 Lower. I installed the Wolf Heavy Duty Hammer Spring that was supplied with the Adams Arms Upper in preparation for shooting the Military Surplus Ammo with the tougher primers.
Went to the range the other day and one third of the Russian Military Spam Can Ammo failed to fire. (32) rounds failed to fire out of about (95) rounds total. I expect a few duds, but that's too high a failure to fire ratio, even for Russian Military Surplus Ammo. It was obvious something was wrong. So, upon further inspection, the rounds that did fire had slightly deeper dimples on them than the ones that didn't fire. The dimples are very prominently seen on the primers of the failed rounds, but consistently just not as deep and not as distinctly shaped as the primer dimples on the fired rounds. I've found some relatively vague instruction on the web on how to install the spring, looked at a few parts breakdowns, etc...even checked out You Tube. This is a huge issue according to the posts I've read about guys having a similar problem. I assume I have the spring in wrong. Does anybody have a source for a better explanation of how to install the spring? |
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I have six lower builds under my belt, and all hammer springs are properly installed. Bill ETA: I JUST CHECKED THEM ALL. |
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Thanks very much everybody! Looking at the diagrams, and reading your comments was a huge help!!!
After reading your comments, and reviewing the images, I found that the culprit was not that the hammer spring was upside down after all. Both legs of the hammer spring are supposed to rest on top of the trigger pin. The lighting must have been a little poor when I did the installation of the hammer spring because I noticed that one leg was under one side of the trigger spring pin. The hammer still seemed to have significant pressure when I was having the problem, even with the one side canted under the trigger spring pin...just having that leg of the hammer spring canted slightly reduced the pressure that is needed to bust a cap, and that's all it took, failure to fire every third round. Using the diagrams and explanations you all supplied, I removed the hammer spring, and reinstalled it the proper way. I didn't have a lot of time to play with it tonight, but I did take the rifle out back, and emptied a 30 round magazine without any failures to fire. Before, every third round failed to fire. Just going through a full (30) round magazine without having any issues compared to the failures I was having, seems to indicate that proper installation of the hammer spring was the culprit. Now, one other question...during my research to determine how to resolve the failure to fire problem, I've also read about High Performance Bolts. I've read that they are more efficient with respect to busting a cap on Military Surplus Ammo, some of them even having a firing pin that is slightly longer, maybe .010" or so I believe. Anybody had any experience with these high performance bolts, and would you recommend them, and why? Anybody know if the high performance bolts will work in the Adams Arms Piston Upper? Thanks so much for your help guys! |
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