Help Rough Chamber

[Klong]

I have a DPMS 300 SAUM that will not eject due to a rough chamber. I have polished it some with JB paste (gray) and it has helped, but not solved the problem. I would just send it back to DPMS, but it shoots 1/2 moa and I would like to keep the barrel. It is new, less than 30 rounds fired. My bore scope finds it has large deep tool marks in the chamber. The brass punches out with a rod with little effort.

What would be a faster way to polish this chamber?

 

[rayjay]

It can't be saved, send it back for rebbling.

 

[p17enfeild]

please post a photo of fired case it will help the the advice, but id send it back you payed for quolaty and you dont sound to have got it !

 

[butchlambert]

Trash got between the reamer flutes and the chamber. Seen this before and if the barrel is long enough, cut it off and rechamber. Polishing will only make a non concentric oversize chamber.
Butch

 

[Klong]

Thanks for the replys!

This barrel is shooting, single shot, at near a 1/4 moa at 200 yards.

 

[watercam]

For what it is worth I had a 6XC chamber in the same condition. I to tried to polish it with limited success. I finally rented a reamer from 4-D Products and ran it in up to the shoulder (but not cutting any shoulder) by hand and it cleaned up my particular chamber. I believe the original reamer used was a bit worn and the rental was newer and sharp (as has every rented reamer from 4-D been). Worth a try, rental runs about $30 for reamer and go gauges.
Mike T.

 

[Rustystud]

Your DPMS has a gas port so setting it back is not an option. Butch has told you the problem with polishing the chamber out. Your messing with it will void your warranty.

It is a new gun and it has a major defect. Send it back.

This is classic case of the QC issue since the new parent company buy out. I own several of the older model DPMS rifles (no issues) and don't reccomend the new ones to my customers.

Nat Lambeth

 

[Kenny474]

Send it back. If you really want to pay good money for a junk chamber than so be it. But I am sure you will get a properly chambered barrel to shoot just as well, probably better.

Or keep it and just deal with having a single shot AR that shoots decent groups.
That makes about as much sense as staying with a girl that cheats on you because she looks good.
Your choice.

But for the record, I had a DPMS AR-10 in .308 that would shoot just as well, so they are not that rare. Send the junk back before you get stuck with it.

And stuffing a rod down the muzzle isn't going to do your muzzle any favors either.

 

[Steve Blair]

That makes about as much sense as staying with a girl that cheats on you because she looks good.

Well said.