M4 feed ramp problems

[Asleep at the Wheel]

Never been on a forum before so I hope I'm posting this correctly. I just built my first AR15 from parts from various manufacturers. I went cheap on the barrel and bought a Citadel 16" mid length at a gun show and put it on a Yankee Hill upper. The problem is the M4 feed ramps suck! The round gets jammed in either ramp almost half the time, but only when charging the rifle, not when shooting. The actual bullet is wedging in the feed ramp and I have to charge it again to push it through. I am pulling the charging handle all the way back and letting go evenly and completely. After comparing the feed ramps on my other Olympic Arms rifle, which has no issues, it's clear the feed ramps on the Citadel barrel are much too narrow. On the Olympic Arms rifle I can charge it as slow as I want and the rounds just jump into the chamber.
Any ideas on how to fix this, or is the barrel junk?

[Dead Man]

Will you take a picture of the feedramp/barrel extension interface and post?

[D-R]

Not normally a betting man, but it is nearly certain that your Citadel barrel does not have an M4 barrel extension. M4 cuts in the receiver will not work well with A3 barrel extensions, and will cause FTF just as you are describing. The tip of the round will catch on the edge between the receiver ramps and the barrel extension. Pics will confirm this.

This post might also help clear up the issue:

https://www.m4carbine.net/showthread.php?t=193&highlight=feedramps

[Asleep at the Wheel]

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[Iraqgunz]

It's hard to tell from your pics. Can you separate the upper and lower and then take a picture with good lighting right into the barrel extension area?

[Asleep at the Wheel]

Thanks for the help guys. I cant, I'm at work right now. That was just a pic I had on my phone. I'm not sure what a barrel extension is though.

[Asleep at the Wheel]

The line where the upper ramps meet the barrel reamps isn't bad though. It seems the same as my Olympic Arms rifle. It's that the bullet actually gets wedged in the narrow feed ramps.

[Iraqgunz]

The barrel extension is that shiny silver thing where the lugs are located. It appears that you have an M4 extension, but that the upper receiver feed cuts (on the upper itself) are crap. It's hard to tell without a better pic.

Out of curiosity did you make sure that the barrel was fully seated into the upper receiver before torquing the barrel nut?


Thanks for the help guys. I cant, I'm at work right now. That was just a pic I had on my phone. I'm not sure what a barrel extension is though.

[Asleep at the Wheel]

Yes, fully seated. Thanks for the help. I would think when you were buying uppers and barrels that they would specify what type if there were different types of barrel extensions. I never saw that. How can I know?

[Iraqgunz]

That's the problem with bargain basement companies. Yours appear to be correct, but without a better pic I can't say 100%.

What you could do is disassemble the upper, get some Cratex bullet point polishing tips and then polish the feed ramps on the barrel extension so that they mate up to the feed cuts. Or get a BCM flat top M4 upper and swap them around. They have blemished uppers for 99.00.


Yes, fully seated. Thanks for the help. I would think when you were buying uppers and barrels that they would specify what type if there were different types of barrel extensions. I never saw that. How can I know?

[Asleep at the Wheel]

Right on, think I'll dissassemble and go to town with the dremel, and if that doesnt work I'll spring for a good barrel. Thanks for the tips.