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Posted: 2/28/2010 4:31:48 PM EDT
| I just finished a weekend long carbine training class. stripped the rifle and cleaned before going to the class but 4 times over 2 days i had misfires because the bolt only closed 3/4 of the way after ejecting a shell and cycling the next one. Used several different mags and there was no connection between the instances and they happened randomly. Shot about 500 times over the course and there was no particular mag that cause the problem. any ideas on what could have caused this? even my instructor was puzzled. |
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Does it have standard or M4 feedramps? Its possible that some of the rounds are impacting below the feed ramp, if so you should see scrape marks just below the feed ramps. You might try chambering a round and then inspecting the round for feed marks. Common issues include sharp feedramps and magazines that cut into the rounds.
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Quoted:
I just finished a weekend long carbine training class. stripped the rifle and cleaned before going to the class but 4 times over 2 days i had misfires because the bolt only closed 3/4 of the way after ejecting a shell and cycling the next one. Used several different mags and there was no connection between the instances and they happened randomly. Shot about 500 times over the course and there was no particular mag that cause the problem. any ideas on what could have caused this? even my instructor was puzzled. So.. how did the AR work prior to this course? 458 |
| Shot fine prior to the class but had never had that many rounds put through it in that short of time period. it has the m4 feedramps. the only time i noticed any problem with the casings were when it tried to double feed one time. stripped it down the other night and cleaned completely. will have to wait til i go shoot it again and see if i can repeat the problem |
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Little trick to keep the gun is the hunt is to combat fouling before it has a chance to build to the point that it can choke the rifle.
It's a simple trick that was first learned in the 60's when the rifle first went into service, around every 200 rounds or so, pull back on the charging handle just enough to get the gas rings to move in front of the exhaust ports, then give the exhaust port a good shot of CLP through the port into the back of the carrier gas section, which will work through the upper bearing areas. CLP has a cleaning in it, and will work to dissolve the following as it sits, and being migrated through the action during firing as well. Side note: if you ever seen a photo of such era solders with a small bottle being retained on there pot via the band, that is the bottle of lube and was an idea place to keep it since the bottle of the time tended to leak a bit and if retained in your pocket for quick reach, could leak and cause skin rashes over time. With current bottle being a bit more secure (not going to leak), using a breast pock on the right hand side works just as well now a days. |
| That was my first thought, not enough lube. I have seen FA's do this during a week long course where we were instructed not to clean our rifles. A shot of lube cured the problems. I lube my BCG heavily. It seems that about 99% of any AR malfunctions seem to be lube or mag issues. |
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