Feeding issue, help!!!

[Blazin]

I recently completed a build and am having feeding issues. My build consists of:
-BHW 1/8 Type 2 barrel
-Colt forged upper
-LBC complete bolt
-Rubber City Armory bolt carrier
-rifle length buffer tube with Wolff extra power spring (installed because initially my BCG would sometimes not go all the way back into battery)
-ASC 10 round mags (I've tried a few)

I don't have pics, but my issue (which happens about twice every 50 rounds) is that the round is stripped from the mag and on it's way in to the chamber and things stop with the round about halfway in to the chamber.

Any advice?

[NugginFutz]

Is the bolt riding over the miss-fed cartridge?

[cory]

What feed ramps does your barrel and your upper receiver have?

[LRRPF52]

Most common cause is a sharp ejector. Radius/chamfer it and the problem will disappear if it's what I think. I've posted pics of it many times in the past.

[Drifter]

Does bolt lock back on the last round fired from a mag?

What ammo?

[Blazin]

I have to look closer, but I do not think the bolt is riding over the cartridge.

M4 feedramps on upper and barrel extension; they match nicely.

Yes, bolt locks back on empty mag every time. Forgot to mention: I'm running an SLR adj gas block.

I want a spare extractor anyway, so I'm thinking on ordering one from Precision Firearms with a new spring and seeing if that clears in up.

[Butterbean]

Is it always the same side of the mag (probably the right side)?

[zbay]

my advice is to perform immediate action (sports) and reengage, how old is the mag?

[LRRPF52]

my advice is to perform immediate action (sports) and reengage, how old is the mag?

Friends don't let friends use SPORTS. The only correct application of SPORTS is this:

Slap the soldier
Pull the soldier around the corner
Observe for witnesses
Release the soldier
Tell no one
Seek legal advice

On PPC-based cases in the AR15, the ejector needs to be radiused, as it will have a tendency to catch on the side of the rim of cases when feeding from the right hand feed lip of the magazine.

[Blazin]

New extractor and spring coming it tomorrow from Precision Firearms, but wow, I DO think it only happens when feeding from the right side of the mag, very interesting. I'll shoot with the new extractor & spring and confirm it's still happening, and attack the ejector from there. Is there a specific brand of ejector you guys have had good luck with? I appreciate all the help.

[davidj]

[QUOTE=LRRPF52;98047]Friends don't let friends use SPORTS. The only correct application of SPORTS is this:

Slap the soldier
Pull the soldier around the corner
Observe for witnesses
Release the soldier
Tell no one
Seek legal advice

Thanks,
I was wondering what that meant.

[LRRPF52]

New extractor and spring coming it tomorrow from Precision Firearms, but wow, I DO think it only happens when feeding from the right side of the mag, very interesting. I'll shoot with the new extractor & spring and confirm it's still happening, and attack the ejector from there. Is there a specific brand of ejector you guys have had good luck with? I appreciate all the help.

If you look closely at the picture, you will see the solution to this easily fixed problem. Radius the ejector, or have someone do it that is competent with tools to where the ejector and bolt won't be damaged permanently.

I use a Brownell's bolt disassembly tool, then chuck the ejector up in a drill and take the edges off that way, using a file and a Dremel. I polish the edge afterwards so that it doesn't have any visible tooling marks on it.

[Blazin]

Ok, so I radiused the ejector, and fired 34 rounds today and I had one failure to feed (round was coming off the left side of the ASC mag). The round was clearly jammed between the ejector and feedramps (see feedramp teeth marks on last pic below). Pics of the malf are below.

I made the ejector radius close to that in post #9 above. The chamber opening of the barrel is nice and smooth, but the feedramps are SHARP! Do you guys suggest radiusing the ejector more, or taking the edge off the feedramp.

[NugginFutz]

If your ramps are as sharp as you seem to indicate, you may wish to polish them.

See this older thread...

http://www.65grendel.com/forum/showthread.php?1875-Polishing-m4-feed-ramps&p=19182&viewfull=1#post19182

I'd also arrange for a proper funeral for that round. It's a goner.

[cst]

I think all feed ramps are sharp as hell ...and if anything nose dives into em,,they'll ger torn up even if they are rounded,,,,.did you try a new magazine? Sometimes if the front of the mag lip is too low the round doesnt get released by the mag in time and causes that kind of jam...they sell this tool to adjust..I used to have similar problem on certain mags from some aluminum mags..

http://www.brownells.com/gunsmith-tools-supplies/rifle-tools/magazine-tools/ar-15-m16-magazine-feed-lip-tool-prod21511.aspx

worth a try before dremeling your barrel.