AR-15 w/ an abnormal F to F problem

BMSMA · November 14, 2009, 05:52 PM

I picked up an Bushmaster AR-15 today. It seems to have a failure-to-feed problem with twist that is strange to me. The bullets of the rounds seem to be getting scratch marks from the lugs after the feed ramp.

It appears the rounds are binding up on the lugs. I am unfamiliar with what could cause this.

I have tied various mags, ammo, and swiching uppers and lower, but with no avail.

Any ideas would be helpful.

BMSMA · November 14, 2009, 07:47 PM

I locked and dropped 6 mags worth with no failure to feeds. However it is still having problems with cycling by hand.

I don't have the ammo or the time today to field test it, but I think this avails my fears of having a bunk gun.

I'll be sure to note if I have any problems in firing it.

rjrivero · November 14, 2009, 08:11 PM

Did you buy this gun used? Check to make sure you don't have a barrel mis matched to the receiver. A M4 upper (with feed ramps) loading into a standard barrel can cause an issue with feeding. The rounds get caught up between the ramp and the barrel.

B. Lahey · November 14, 2009, 08:34 PM

Here's a photo to help figure out if you have a feedramp mismatch.

November 14, 2009, 05:52 PM	#1
BMSMA Member Join Date: March 18, 2009 Location: Here Posts: 51	AR-15 w/ an abnormal F to F problem I picked up an Bushmaster AR-15 today. It seems to have a failure-to-feed problem with twist that is strange to me. The bullets of the rounds seem to be getting scratch marks from the lugs after the feed ramp. It appears the rounds are binding up on the lugs. I am unfamiliar with what could cause this. I have tied various mags, ammo, and swiching uppers and lower, but with no avail. Any ideas would be helpful.

November 14, 2009, 07:47 PM	#2
BMSMA Member Join Date: March 18, 2009 Location: Here Posts: 51	I locked and dropped 6 mags worth with no failure to feeds. However it is still having problems with cycling by hand. I don't have the ammo or the time today to field test it, but I think this avails my fears of having a bunk gun. I'll be sure to note if I have any problems in firing it.

November 14, 2009, 08:11 PM	#3
rjrivero Senior Member Join Date: November 17, 2008 Location: NW Ohio Posts: 1,399	Did you buy this gun used? Check to make sure you don't have a barrel mis matched to the receiver. A M4 upper (with feed ramps) loading into a standard barrel can cause an issue with feeding. The rounds get caught up between the ramp and the barrel.

November 14, 2009, 08:34 PM	#4
B. Lahey Senior Member Join Date: March 17, 2008 Location: Indiana Posts: 2,857	Here's a photo to help figure out if you have a feedramp mismatch.