I have an Armalite AR180B with a tight chamber. I already posted to the AR180 forum, but I have a more general question I thought I might get help with here.

Many people told me to bring the gun to a gunsmith to have the chamber reamed out. I talked to a friend who is a gunsmith/manufacturer and he told me he wouldn't do it because of the possibility of "bell pressure" (I think that's what he called it) where the reaming exaggerates the pre-existing chamber flaw and then further firing stresses it in a non-uniform way, creating a potentially dangerous situation.

He suggested firing a lot of rounds through it to try and break it in. He also suggested dropping some oil over the shoulder of the rounds on a full mag to try and make things run smoother. Initially, the gun would fire 10-15 rounds before heating up and I'd start to get failures to fully chamber a round. It would then continue to fail every other round or so til it cooled down. After I tried the oil trick, it seemed to run great - I put a few 30 round mags through it without fail.

In another post (link below) someone said it was dangerous to drip oil over the rounds, and that a chamber should be dry.

www.ar15.com/forums/topic.html?b=3&f=62&t=261001

I don't know what to believe! Any help is greatly appreciated!

Note: I thought about going to Armalite with this but too many horror stories about their customer service led me to try and fix it locally.

How do you know the chamber is "tight"?

In what area is it "tight"? Headspace, base, what?

Is it a .223 Remington, NATO, or what chamber? What is it supposed to be?

Are you shooting factory ammo or reloads? If reloads, are you bumping the shoulder back far enough? So many times from what you describe, it is improper sizing of the brass that can cause these problems as you describe.

Re-cutting an existing chamber is tricky and you can end up with a glorified tomato stake if not correctly. This will also void any warranty or help from Armalite if you do this. In the end, you just may have to send it back. Afterall, they took your money and it sounds that they have given you a substandard product.

try an polish the chamber no need to re ream it out.

Quoted: Note: I thought about going to Armalite with this but too many horror stories about their customer service led me to try and fix it locally.

Believe NONE of what you hear, and only HALF of what you see.