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Posted: 8/1/2006 12:22:03 PM EDT
| I've put about 250-300 rounds through my new bushy m4 a3, mostly Remington UMC and Winchester white box(usa olin stuff) without a hitch. Today I fired some Federal Tactical Load stuff my dad had from his swat days. It has silver brass and the projectile is flat (for lack of a better description, projectile is shorter than a fmj rem umc round) instead of pointed at the end. I had a failure to feed where the bolt came all the way back behind the round, and fed it straight into the feed ramp causing the bullet to be forced back into the casing and resulted in the gun jamming. I've shot about 30 rounds of the same ammo without this problem in the past. This also happened with some remington hollow point stuff today. My question is, this doesn't seem like a short stroke ftf. Is this caused by magazines or what? This occured with to different mags. These are the only two problems I've had with this gun, just curious to what causes it. |
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The short answer, The AR rifle feed angles (feed ramps and front of mag distances from them) where designed to work with the standard 55-62 FMJ bullet designs. To allow the rifle a greater range of ammo, Colt introduced the improved feed ramps (extended and lowered into the upper receiver) found on the True M-4 rifles. As pointed out, sometimes other mags will feed better than others when it comes to non-standard ammo for the rifle (again, FMJ in 55 and 62 being the standards), or just tightening the mag release button a wind will help (holds the mag a little tighter and helps prevent downward canting of the front of mag. Now if all else fails and the ammo just doesn't want to feed no matter what mag you try or how tight the mag release button is, you can band-aid the rifle/mag into cleanly feeding HP rounds by simply inserting a match book cover in between the back of the mag and the mag well. This cants the front of the mag more upwards, and prevents the bullet tip from making contact with the upper receiver below the feed ramps during feeds (read setting the bullet back in the case). |
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