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Posted: 4/4/2004 5:28:41 PM EDT
| I just acquired this AR in trade and got a few "issues".. It has Mega lower with DPMS parts kit and unknown refinished A2 upper with newer Bushmaster 14.5" M4 with fake(sleeved) Vortex. While test firing, I noticed the action was cycling much slower than my other ARs and some rounds seem to cause A LOT louder report and noticeably larger flash. Also, I had hard time keeping it on the paper @75'. What do you guys think?? I tried 3 different ammo brand with same results. Head space?? Louder report/ larger muzzle flash , slow cycling action?? related?? Thanks. Joe |
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Oh, where to start????? Let just jump in with both feet and cover the report loudness. If you think your 14.5” barrel is loud and has a fireball, you should try an 11.5” barrel. Generally, the gun power of the round will burn for around 16” of barrel. Any barrel shorter than this means that the gunpowder is still burning when the bullet leaves the barrel, Hence the fire ball that your getting out of the front of the rifle (read louder and more flash). As for the action cycling slower, you may check the extractor spring and the buffer. If a heaver buffer is being used in the rifle, then this will slow the cycle rate. In regards to the extractor spring, if the chamber was rough, or the rifle had problems with the extractor retaining the rim (read slipping off) and pulling the spent cases out of the chamber, a stronger spring or D-fender may have bee added to add tension to the extractor. The round may still be slightly bonded to the chamber on ejection, but the new stronger tension on the extractor will retain the spent case rim, and remove it from the chamber. This bonded effect of the spent case to the chamber will slow the ignitial bolt movement, which in turn, slows the cycle rate. As long as the bolt is locked back after the last round of the mag is fired, the band-aid is working. Note: We aren’t big fans of band-aids, but would rather solve the original problem than just masking it with an Add-on. Now keeping it on paper, If you are able to shoot other AR’s with consists, then you need to give the barrel a once over. Start off with the muzzle attachment to confirm that the bullet is not striking the device as it leave the barrel. If you have copper streaking on the inside of the device, you have found the problem. The second item to check is the muzzle crown. If the install of the device effected the crown, such as silver solder flowed into the bore/crown, then this will effect the flight of the bullet as it leaves the bore, and could even be causing the bullet to strike the muzzle device. Last would be the overall condition of the plating and rifling in the barrel. If the device was silver soldered to the barrel with too much heat, it may have peeled the chrome lining, then were back to bullet traveling the last inch of barrel (most important part) with problems (read not a clean travel/ release from the rifling), and again, could be striking the muzzle device. If you haven’t guess it by now, Check to make sure that the bullet is not striking the muzzle device on the way out. Even a worn barrel will still print in the 5 MOA, it when the bullet is being deflected off the muzzle device that you get the 12” plus shot gun grouping. Now without the rifle in hand to inspect, or breaking out the crystal ball, this is as far as which to speculate. Post back with your findings, and we can take it from there. |
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