M14 Forum

angelonm

Those are heavy bullets..
Maybe your action spring isnt strong enough?
Look in the direction of what USMC indicated.

Whatsinaname181

Hey thanks cobra, youre a big "help". Why dont you build something constructive to say.

Angelonm, I would think the spring is strong enough- its pushing the projectiles back into the casing during feeding (when it gets caught up on the feed ramp). I know the ramp is at least part of the problem, there is a lip there that the projectiles are nosing right into. Now, as USMC said, these rounds arent even supposed to be this low. ill do some comparing with my other two AR's and see what the problem is. Again, this is a sporadic issue- sometimes it does this and sometimes it doesent.



This rifle is a good peice. This is the only issue ive had with it and is an absolute tack driver.

Edit- OK. I just made some magazine length dummy rounds. they feed fine. im easing the bolt forward to see where the rounds are making contact with the feed ramps. the projectiles are making contact with the feed ramps in the same place as my bushmaster. i just cycled them with the rounds ive been having issues with (PPU 75gr .223) and they fed as well. The magazine is sitting properly inside the well and is greeting the feedramps at the proper height (it would seem).

USMC, im wondering as to what you were saying about the speed of the cyle of operation...

Im going to keep trying to replicate what has been happening and find and answer for it.

CHARLIED308

I had an issue with an AR-15 doing the same thing and it drove me nuts. I manually cycled rounds through the rifle to troubleshoot the problem and it fed fine. When I fired it, I still had the same problem you are describing. I had to send the rifle back to Bushmaster twice before the problem was corrected. The paperwork enclosed with my rifle was not very helpful in telling me what corrective action was taken.

Does your rifle malfunction with lighter weight bullets, such as 55g and 62g rounds? What is the barrel length?

FICK_USMC

The problem is the open meplat of varmint style bullets like the Varmint Grenade, or the relabeled Varmint Nightmare's from Midsouth or bulk varmint bullets from Midway. These varmint bullets have a very large opening at the tip to facilitate rapid expansion upon impact with small animals. The AR is not designed to feed these hollow points reliably. I'm sure you could reshape the feed ramps, or slow down the action to make them work 100% though. People wanting to load great ammo at a lower cost are often attracted to these bulk varmint bullets. They shoot great, and are very accurate. But the AR's cyclic rate, and feed ramps do not like them. A great alternative for cheap and accurate ammo is to use pulled GI 55, or 62 grain projectiles. Varmint uppers are available, but I believe they are modified to handle this type of ammo to minimize feeding problems.

82nd ABN

If it doesnt specify an m4 feed ramp it's not. I would pull the barrel send it back and have the correct extension installed. It would solve your problems
PS all I shoot from my two AR that are built right now is 75 gr bh match. No feeding problems at all. One has a rifle extention in an a2 upper the other a flat top with the m4 extention.

jmoore

The PPU 75gr Match ammo's bullets have a fairly small meplat, but not tiny. I'm on my third case of 'em with no functioning dramas.

If MagPul followers in your metal bodied mags don't cure the feeding problems, and the feedramps are not the problem, then there could possibly be a mag catch placement problem in the lower- too low- and fairly unlikely!

It seems most likely though, that most of the previous posts have tackled the major areas of concern.

dprice3844444

also note,anytime feeding problems occur,1st check the extractor and make sure they have a good spring,the nylon piece and the donut.