Dpms Chamber Tight

[D.Hayden]

I have a JP Upper, that will feed/fire anything, and an older DPMS upper that's quite finicky.

Is there an easy way for a all thumbs kind of guy, to loosen up the chamber a tad?

Something simple like a cotton mop with a little polishing compound on it or something?

Or do people send them to get reamed to .223 Wylde or ??

Thanks..

[Dan Sierpina]

The best way, is pull the barrel and have a reamer run in by hand. Next best, reamer extension, run a reamer in by hand. You might have some luck with the cotton swab with abrasive, after all, look at the Grand Canyon.

[EricW]

Try JB on a 45 cal bore mop with a power drill.

[Dan Sierpina]

Dave,

My Grand Canyon joke aside. Is it not quite going into battery? Are bright spots showing on the brass, just ahead of the extractor groove? That will tell you if the chamber is a bit short, or the original reamer was undersize. The problem with the abrasive is you can't control where any metal might be removed. Pulling the barrel is the best way to have a good chamber.

No more jokes

Edited February 7, 2007 by Dan Sierpina

[D.Hayden]

I had reloaded some rounds, with the sizer die adjusted wrong.. just enough so they wouldn't fit into the JP case cage.

The JP still fires them fine, the DPMS will occasionally gorp on them.

It's really just for practice ammo, but with sand/dust etc. (I'm thinking MGM Ironman here), I figure the chamber has more of a chance of causing me problems.

If the mop and JB would help a little.. what the heck.

If it needs to be reamed, I wouldn't even try it.. I'd probably end up putting it though the crown..

[uscbigdawg]

Dave,

The David Benzick method works well too. Steel wool wrapped around a cleaning brush, some JB and chuck it into a drill on a cleaning rod. Let it spin until you get happiness. If that doesn't work, check the throat dimensions. Both OAL's might not work for both rifles.

Rich

[smokshwn]

+1 on Eric's idea.

I used a .30 cal bore mop coated in JB paste in a drill.

[Dan Sierpina]

I had reloaded some rounds, with the sizer die adjusted wrong.. just enough so they wouldn't fit into the JP case cage.

The JP still fires them fine, the DPMS will occasionally gorp on them.

It's really just for practice ammo, but with sand/dust etc. (I'm thinking MGM Ironman here), I figure the chamber has more of a chance of causing me problems.

If the mop and JB would help a little.. what the heck.

If it needs to be reamed, I wouldn't even try it.. I'd probably end up putting it though the crown..

Going by your description, the DPMS barrel is cut with minimum headspace. Sounds like the JP is almost to the No-Go gage. You can try the mop in the drill, but, like I said, you can't control it to the degree of having the chamber properly reamed.