Home Forums Hunting & Shooting Gunsmithing A R feeding problem

customer comes in with bushmaster, not really up on the black rifles so any ideas will be considered. When bolt is released the round will jam half way in chamber,bolt just rides over and locks everything up halfway the round . Was thinking bad magazine BUT this happens on every mag this guy has (6) happens with full mags,half full,or with only one round in mag. If round is single loaded and then mag insreted and fired rifle works fine,just when cocking and loading manually does thi jam up happen. What shoulid i be looking for? Thanks

Well, by the sounds of it, it's going to either be a feed ramp issue, or, a magazine issue. It is possible to get a gun with a screwed up barrel extension where the feed ramps are mis-cut. So what I would do is install a safe firing pin, one without a tip, and hand feed some ammo from the magazine and watch to see what it is doing.

It could also be a magazine issue. You say how can that be if all 6 magazines do the same thing? Where all magazines do the same thing, then you might look at the magazine catch to see if it is holding the magazines at the correct height to feed.

The fact that it feeds fine once it gets going doesn't necessarily mean anything since the rounds can accidentally bounce up in front of the bolt as it moves back and forth. Unless there were something I could see that was obvious, I would start there. Good luck!

i was thinking mag catch also, am going to get big rubber band and hold mag tight in place and see what happens. customer told me last night he replaced buttstock ,then feeding problems started. not sure how that would have any effect on feeding ,but he could have screwed up something. thanks

The buffer and buffer spring tube is part of the butt stock assembly and the buffer spring is what drives the bolt forward... Look there and see if something is interfering with it's movement. Speed and momentum is what feeds this gun. A sluggish bolt/carrier can cause mis-feeds with this gun.

aahhhaa new stock came with new spring changed to old spring and bambambamect

Good deal, thanks for letting us in on the spring problem. Malm had it nailed

that's what i like about the fire good people willing to help!