AR Sponsor
Posted: 1/12/2008 8:37:05 PM EDT
|
I got a new Bushmaster M4A3 patrolman's carbine. First off: Sometimes I can fire a whole clip without it failing to feed. Then sometimes it will shoot one or two then ftf. I have had about 320 rounds through the gun. Shooting Wolf Mil. Classic. Sometimes I think it's short stroking because it will fire and then next time i pull the trigger "click", no round loaded in the chamber. Would the rifle still short-stroke even when new? I've taken it apart and cleaned it twice both after both of my firing sessions. I always made sure the gas rings were 120 degrees apart when I reassembled it. Second thing: I don't have M4 extended ramps cut at all in my upper receiver. I was assuming that since I had an "m4 bushmaster" with the barrel cut in for the grenade launcher that I would have the extended feed ramps that decrease feed problems? Thanks folks I know this is my 2nd post but you got to start somewhere. |
| Well I'm not a big fan of wolf ammo and have noticed some quality issues lately at the range . I myself had a batch that was short stroking in my AK and SKS . I don't use it im my bushmaster's or my DPMS AR's . Also try a mag with a good follower . Sounds like a shortstroke issue the way you described it but you never know . As far as the feed ramp , you could polish it out as well but I would go simple trouble shooting and work my way up . |
| Check for fouling of your bolt carrier key. Dirty ammo can foul it up fairly easily, causing gas blockage, and short stroking... lot of people use a pipe cleaner to swab it... I just soak my whole carrier in Carbon Killer during my cleaning process. |
try a heavier buffer. its works for the issue you describe. M4 feed ramps shouldnt have anything to do with your prob. |
|
Was the rifle fully cleaned and CLP lubed before being fired? Did you check the key bolts to confirm that the are tight at 37in lbs. When lubing the buffer and recoils spring, did you notice if the end of winds of the recoils spring was scrapping down the inside of the tube, and you have confirmed that the spring is 10.5"? Have you loaded a single round into the mag, charged and fire that round to find the bolt locked back on bolt catch when the rifle was freshly cleaned? Regarding the jams, is the problem a low feed with the tip of the round crashing into the upper receiver below the feed ramps (will be marks on the upper receiver) or is the jam with the bullet tip just starting to make it up the feed ramps/ round not fully out of the mag? |
|
No i didn't clean/lube it before the first time i fired it. Could this be just a break-in issue? and it will work itself out? I'm pretty sure the bolt will lock back after the "last shot" I'm not really getting jamming issues. It's just not loading the next bullet always. |
The rifle is packed with assembly grease for long term storage (read so it will not rust before someone buys it), hence you have just solved the problem with your own answer. If you have any questions on cleaning and CLP lubing the rifle correctly, www.ar15.com/forums/forum.html?b=3&f=7 |
|
Copper solvent with a chamber brush to clean the chamber/a standard bore brush to clean the bore, then all the copper solvent completely removed. The rest of the rifle cleaned and lubed with CLP, not standard oils or Hoppes copper solvent (read Hoppes solvent and CLP (BreakfreeCLP if you need a source in less than a gallon and the 16oz spray can the best value since it goes for about $10 at Walmart/sportsman) makes a hell of the sticky mess when it mixes, and non CLP type products don't do well with the AR system since they do not contain a cleaner). Please click the link I listed and do a bit of research on cleaning and lubing the rifle correctly. Myself, I use Sweets to clean the chamber/bore with brass brushes since it does not leave any protective coating that must be flush out (even after dry patch swabbing) before the rest of the rifle is correctly CLP lubed. Note: if the rifle is to be stored, then CLP can be used for this but it must be removed from the bore (dry patch swabbing) before it fired. Also, CLP does contain Teflon so even with the bore dry patch swabbing to remove the lube portion, it will take about 14 shots to fire out the remaining Teflon from the bore before the rifle/barrel settles in and start to group right. Added: Some of the Rem oils are LP only (with Teflon) and contain no cleaning agents. |
|
FWIW: I had the same problem with my BM M4 style upper and JHP ammo. The rounds would hang on the low end of the feed ramps. I discovered that there was a very minute 'step' where the barrel extension met the receiver. a couple of minutes with dremel and RUBBER polishing bit solved it. The upper runs 100% with all the ammo I've used since. |
AR Sponsor