Help with new Build Issue

[Joelski]

Could be a tolerance issue, even with reliable, well regarded parts. I've had an enhanced bcg barely move in a billet upper, swapped it to a forged one and it hand cycles easily, even dry.

[Big_Tom]

The feed ramps would be my next thing to look at.

The upper and barrel extension may not line up as good as they should.

A little dremel time would fix that if so. Or just some good ol sand paper and a finger job.

Can you get a pic of the feed ramps with the upper detached from lower. Get them from the bottom where the mag would be.

[GOST]

Could be a tolerance issue, even with reliable, well regarded parts. I've had an enhanced bcg barely move in a billet upper, swapped it to a forged one and it hand cycles easily, even dry.

You're probably right, tolerance stacking is probably it.

[Joelski]

You're probably right, tolerance stacking is probably it.

Of in his case, matching, +/- a RCH.

[Stone]

On second thought I would just keep swapping parts at random until someday something happens. And whatever you do don't check the feed ramps. Take a few more videos as well, I thoroughly enjoyed them.

[Stone]

The feed ramps would be my next thing to look at.

The upper and barrel extension may not line up as good as they should.

A little dremel time would fix that if so. Or just some good ol sand paper and a finger job.

Can you get a pic of the feed ramps with the upper detached from lower. Get them from the bottom where the mag would be.

Thanks Tom, seeing as how that was mentioned several times already maybe a third times a charm.

[UWone77]

Thanks Tom, seeing as how that was mentioned several times already maybe a third times a charm.

LOL.... and... a dremel to feed ramps?

NOOOOOOOOOOOOOOOOOOOOOOO!

[Stone]

LOL.... and... a dremel to feed ramps?

NOOOOOOOOOOOOOOOOOOOOOOO!

Sometimes I just want to stab myself in the eye with a sharp pencil....

[cjd3]

It's been recommended to me to use a Cratex polishing bit to blend the feed ramps with the barrel extension. Last ditch effort attempt. However, before you do that, have you swapped out the bolt catch? Could the carrier be riding it?

[tappedandtagged]

Sorry I've been away for a while. Work has me swamped.

Here's a pic of the feed ramps. They look OK to me, but I'm no armorer. Edit: I looked at several bullets that I've been chambering. They're buggered. So I guess the feed lips ain't so OK after all?

[Big_Tom]

Sometimes I just want to stab myself in the eye with a sharp pencil....

LOL.... and... a dremel to feed ramps?

NOOOOOOOOOOOOOOOOOOOOOOO!

Thanks Tom, seeing as how that was mentioned several times already maybe a third times a charm.

Yeah I know I just wanted to see if y'all actually read my post. And I skimmed the thread seeing if any thing wasn't mentioned. Guess I looked over the parts about checking feed ramps. And I just like throwing my 1cent around.

[tappedandtagged]

I swapped buffer, springs and charging habdle again, just to double check. No go still. After it failed to strip the round, Inpulled the charging handle back again and "hammered" the partially stripped round. It went forward, free of the mag lips, yet the bolt stayed hung up. I removed the mag, and the bolt went home, chambering a round. I was able to duplicate this several times with different mags.

[tappedandtagged]

Yeah I know I just wanted to see if y'all actually read my post. And I skimmed the thread seeing if any thing wasn't mentioned. Guess I looked over the parts about checking feed ramps. And I just like throwing my 1cent around.

I appreciate your 1 cent! Thanks for your input. Hopefully I'll be able to figure this put soon enough. Its been on the "back burner" for too long.

[Big_Tom]

I appreciate your 1 cent! Thanks for your input. Hopefully I'll be able to figure this put soon enough. Its been on the "back burner" for too long.

Anytime I know how much of a headache it can be when you can figure out the issue. I like to giving people a good chuckle a time and again. Lol

[Stone]

Yep, just having a little fun. It looks like there are a couple of burrs on the feed ramps from machining. If it is, it will dig into the copper jacket and stop the round dead in its tracks which is what it looks like from the original picture. I just resolved the same issue on one of my rifles at 3K rounds, it was bad and doing the same thing. I circled the area that looks suspect, any way to get a clearer shot? Are the bullets gouged real bad? Are you seeing excessive copper and brass shavings?