Rounds wont feed - AR15.COM

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Posted: 5/10/2008 8:40:10 PM EDT

Click here to view pictures

I have been having trouble with my new build. I will be able to fire a round or two. But then things jam up. Above link shows what the rounds look like after getting jammed up.

I am using rebuilt mags.

I have cleaned and lubricated bolt and carrier.

I have made the extra turn on the mag release. Still have problems.

Posted: 5/10/2008 11:00:25 PM EDT

[#1]

What are the specs on the build?
Are you loading the mags to capacity?
Have you tried other magazines?

Posted: 5/11/2008 12:14:38 AM EDT

[#2]

Was the rifle fully cleaned and CLP lubed before it's madden run?

Was the first shot out of the rifle from a mag with only a single round loaded/fired to check for short stroking, hence the bolt did lock back on the bolt catch after such shot was fired?

Posted: 5/11/2008 9:32:01 AM EDT

[#3]

20" bushmaster chrome lined barrel
A1/C7 upper from PK firearms
Bushmaster bolt and carrier

Cleaned and lubed with CLP before firing.
I have tried different mags.

I have not tried firing with one round in mag to see if it locks back.

Posted: 5/11/2008 2:15:10 PM EDT

[#4]

Quoted:

I have not tried firing with one round in mag to see if it locks back.

Do so, and get back to us on the results.

Posted: 5/11/2008 3:34:28 PM EDT

[#5]

I'll give that a try and get back with ya. Thanks

Posted: 5/16/2008 4:48:42 PM EDT

[#6]

Made a quick trip to the range this afternoon.

I put 1 round in a mag and fired. I did this 3 times. Pics below show what happened 2 out of the 3 times.

Link to pictures

Posted: 5/16/2008 10:18:47 PM EDT

[#7]

The rifle is short stoking.

Start off my checking the key bolts to confirm they are tight (37 in lbs).

Look at the back of the trigger/tail of disconnector for signs of hammer wedging (read dent or white line). If such is found, remove .040 off the tail of the hammer.

Pull the recoil spring and confirm that the end of coil is not bur'd and scraping down the inside of the tube.

If you are running a A-1 stock, confirm that the butt stock screw is not too long and protruding into the receiver extension cavity. If a carbine stock, confirm that the recoil spring is 10.5" and you are using a carbine buffer.

When you solvent chamber brush clean the barrel, make sure to remove all traces of the solvent. When you CLP lube the upper bearing surfaces, go a bit on the heavy side for break in, including not to forget to lube the buffer and spring as well.

Posted: 5/18/2008 7:38:12 AM EDT

[#8]

Thanks, I will check each of your suggestions.

Posted: 6/3/2008 11:56:57 AM EDT

[#9]

I have a similar problem as akray, this is a custom build M-4 kit from M-A parts, I have tried new and used mags even my Army issued mags also tried a different bolt and adjusted the mag catch tighter. My rifle is not short stroking it cycles fine but is causing a lot of damage to the rounds as they load. The rounds look just like the ones in the first photo posted by akray but when a full mag is used (28 rounds) the bullets are even being bent at the top of the case just before it begins to neck down. This is leaving to distinct scratches on the bottom of the case, the bottom being the bottom of the case when it is loaded in the mag, the top being the visible part of the round from the top of the mag. The scratches are about 3mm apart and consistent, I think they are from the star chamber. The rifle fires and cycles fine and is fairly accurate these scratches are not as bad with one or only a few rounds in the mag but the more rounds in the mag the worse the scratches and bending or the bullet. Wolf ammo seems to not scratch much, probably due to the steel case, used Remington UMC and also so hand loads with Winchester cases, all had the same problems that had brass cases.

Thanks in advance for any help.

Posted: 6/3/2008 12:35:27 PM EDT

[#10]

Quoted:
I have a similar problem as akray, this is a custom build M-4 kit from M-A parts, I have tried new and used mags even my Army issued mags also tried a different bolt and adjusted the mag catch tighter. My rifle is not short stroking it cycles fine but is causing a lot of damage to the rounds as they load. The rounds look just like the ones in the first photo posted by akray but when a full mag is used (28 rounds) the bullets are even being bent at the top of the case just before it begins to neck down. This is leaving to distinct scratches on the bottom of the case, the bottom being the bottom of the case when it is loaded in the mag, the top being the visible part of the round from the top of the mag. The scratches are about 3mm apart and consistent, I think they are from the star chamber. The rifle fires and cycles fine and is fairly accurate these scratches are not as bad with one or only a few rounds in the mag but the more rounds in the mag the worse the scratches and bending or the bullet. Wolf ammo seems to not scratch much, probably due to the steel case, used Remington UMC and also so hand loads with Winchester cases, all had the same problems that had brass cases.

Thanks in advance for any help.

First off, Welcome to the site!!!

If you can post a photo of the scratches, we should be able to narrow down the problem to a single area to tweak/correct. What is does sound like now is you have end of feed ramp burs that need to be stoned, but would like to confirm such before advising such.

Posted: 6/3/2008 1:50:20 PM EDT

[#11]

Thank you for the welcome, Here are some photos. Notice how the bullet and case are bent!

photos

Posted: 6/3/2008 3:55:24 PM EDT

[#12]

Bent bullet is from a low feed (hit the upper receiver below the feed ramps).

Case scraps look to be coming from end of barrel feed ramps burs, but does bring back the question of why the low feeds?

Bring me up to speed on the mags you rebuilt, are they USGI?
Will they pass a feed test, hence load three rounds into one, push the back of the rim down alone, and let it snap back up with the final results being the case is seated against the entire feed lip area?
Are you having problems will the follower binding in the mag bodies if you replaced the followers as well.

Posted: 6/3/2008 5:24:34 PM EDT

[#13]

Been there done that, looks like bad mags. Please don't say there USA mags.

Posted: 6/4/2008 11:27:09 AM EDT

[#14]

Do you think the low feeds could be a result of the lower reciever not holding the mags at the proper height? What would you recomend to use to remove the burs on the feed ramps/star chamber?

Posted: 6/4/2008 12:50:31 PM EDT

[#15]

Small jewelers file to knock off the end of barrel ramp burs, but back to the mags, are these USGI or cheap knock off types. If knock offs, then see if USGI mags solve the problem before tweaking the rifle for the less than desirable type mags.

Posted: 6/4/2008 1:43:38 PM EDT

[#16]

I am using USGI and Colt mags that have been working fine in my issued Colt M4 so I dont think its my mags.

Posted: 6/4/2008 5:39:24 PM EDT

[#17]

Could be that the mag catch was produced wrong, or the slot for the catch milled too low in the receiver.

Since you have another rig, check the heights of the top of the retained mags in both rifles/receivers against one onther.

[ARCHIVED THREAD] - Rounds wont feed

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