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Posted: 3/21/2007 7:36:37 AM EDT
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I've had an upper custom built. In shooting it, I get a failure to feed (?) I think. Gun fires, then click. Cannot pull the charging handle back, no matter how hard I try hence the gridlock. Have to pound on the forward assist until I hear the click of the bolt seating. Then shotgun the upper, cock the hammer, close it and fire the round. It may fire six or so rounds then do it again. Tried eight different mags, and numerous different ammo. From 55 grainers to 77 grainers. Doesn't seem to matter. A couple times it short stroked, failing to pick up the next round. At least when that happens I can just pull the charging handle back and fire the next round. Seems to always lock back at the end of the mag. What say the experts? 
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Confirm that you are getting last shot bolt hold open (full stroking) all the time. Next ammo type? If reloaded ammo, time to gauge the loads to weed them out as the problem. Also confirm the chamber and the throat leade of the custom barrel, and make sure that the ammo you are using is compatible with it. |
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I believe it locks back every time. Ammo tried varied from commercial, military, reloads using a smallbase sizing die. Barrel is a White Oaks special purpose, 18" with a 1/7 twist and wilde chamber. As stated, ammo tried was 55 grain, 62 grain, 68 grain, and 77 grain. Edited to add, the mags I've tried (8) include 20 and thirty rounders from C Products, grey anti tilt followers, chrome-silicon spings. These mags have run flawlessly in several other ARs. ??????????? |
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Again, confirm if the chamber is 223 or 5.56 Nato, and the throat leade is standard or on the short side for match hand loading. As for the reloads, need to confirm that the cases are being sized correctly (sizing die touching the shell holder under ram pressure, the bullet crimp is not set too tight, buckling the shoulders, the cases are trimmed correctly, and you are not loading the bullet out long and in gauging the bore/throat rifling at loading (can happen even with standard loads if the chamber is not set up for standard ammo). |
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Update.... Sent the upper back to the builder. Called him today he said he tested it and couldn't get it to malfunction, to check the lower, specifically the spring. He said he fired numerous brands of ammo including wolf through it without a catch. I'll see what happens. Tried the upper on a couple different lowers before sending it back...still had the same problem. The chamber is a Wilde chamber which is suppose to work with either .223 or 5.56. Upon it's return I'll test and update. Meanwhile I'll change out the spring in the stock. It's a standard A2 rifle stock. The lower is a RRA. |
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