DPMS 24 inch 223 9 twist

[ebb]

I bought from a friend a DPMS 24 inch varminter, I have had it for years and fired many shots and it was not new when I got it. The accuracy has fallen off as of late. I haven't borescoped it yet so it could be any thing. If it is in fact fire cracked from excessive heat and many rounds, is it possible to set back the barrel? I know this is done on bolt rifles all the time, but I have never heard of this on an AR. It was a very accurate rifle for a long time, and I am not sure if I will get another that shoots as good. If it can be done what would you do with the gas port? Would you just make a shorter gas tube and leave all else alone?

 

[Bully]

Unless you're doing the work yourself, considering the cost of having a qualified 'smith take it all apart, set the barrel back, and move the gas port or buying some new parts, for a couple hundred bucks, buy a new barrel. That would be my suggestion anyway. Barrels are an expendable component on a rifle.

 

[strut64]

Try an effective cleaning first. Make sure to get at any copper accumulation Cleaned out. There are lots of good copper cleaners. I use Bore Tech Eliminator, but , There are others.

 

[STRSRLVR]

Try an effective cleaning first. Make sure to get at any copper accumulation Cleaned out. There are lots of good copper cleaners. I use Bore Tech Eliminator, but , There are others.

I would give it a good cleaning like strut64 said with a few cycles of the eliminator followed by some JB bore compound and then elimator again. Just make sure to clean out the gas tube & hole to make sure there is no JB stuck in there by some slim chance. If that doesn’t bring the accuracy back it’s probably time to thrown on a new tube.

 

[mic2377]

Good cleaning, and if that doesn't work, then new barrel. AR barrels are not expensive and they are very easy to swap. There are lots of great barrel makers that would likely make you happy with their accuracy.

 

[243Mendoza]

get rid of the carbon ring with jb

 

[Txhillbilly]

When you say it has been shot a lot, How many rounds have you put down the barrel?
It takes a lot of 223 rounds to shoot out a barrel in an AR, the barrel may just need a good cleaning. If not, there are many quality barrels available to replace it.
If you only change the barrel, I'd stick with the rifle length gas system. It works best in 18" or longer barrels.

 

[TAJ45]

When you say it has been shot a lot, How many rounds have you put down the barrel?
It takes a lot of 223 rounds to shoot out a barrel in an AR, the barrel may just need a good cleaning. If not, there are many quality barrels available to replace it.
If you only change the barrel, I'd stick with the rifle length gas system. It works best in 18" or longer barrels.

I'm thinking that rate of fire (hot bbl) is even more of a factor than round count.

 

[ebb]

Its never been rapid fired. I cleaned it with wipe out and JB paste, it should be clean but I will borescope it and post my findings. With it's pet load it used to shoot little tiny groups, not so much lately. It was such a good barrel I didn't want to loose, but It did come right off the DPMS pile.

 

[boltgunluvr]

I'm thinking that rate of fire (hot bbl) is even more of a factor than round count.

I believe this statement to be true in many situations.

 

[JBT47]

Its never been rapid fired. I cleaned it with wipe out and JB paste, it should be clean but I will borescope it and post my findings. With it's pet load it used to shoot little tiny groups, not so much lately. It was such a good barrel I didn't want to loose, but It did come right off the DPMS pile.

Hopefully since you cleaned it, Accuracy will return. I look forward to your updating this thread with your borescope findings.

I had a DPMS heavy barrel and it shot fantastic. Like a dumba$& I can be at times...I sold it. Haven’t had another AR since that would come close to that one.

 

[ebb]

The cleanings haven't helped, I will borescope it tonight.

 

[Downhill]

I have seen a couple AR barrels start to foul at the gas port. For some reason copper started building up at the muzzle side of port. Once cleaned (lapped with JB) the accuracy returned. If this is the case you can feel it with a tight patch.

 

[mic2377]

Curious to hear what the bore scope looked like...

 

[urbanrifleman]

It is nearly impossible to slow fire burn out a 223 barrel. It is probably dirty.

Bore Tech Eliminator. Let it soak over night. JB Paste the first 12 inches several times.

 

[searcher]

I'd check the barrel nut for tightness and your lockup pins for wear. Sloppy upper-to-lower receiver fit can do that as bad or worse than a shot barrel. Maybe put in a plastic $2.99 bushing to take up slop between the two, check barrel nut / hand-guard nut and replace the mainspring. Mainsprings, when they start to sack, change the pulse of the rifle enough to also alter accuracy from where it was. If you have a flash hider or brake - check for tightness. Check tip of firing pin for wear and any carbon build-up that might prevent it from moving to the full-forward position. Check trigger for grit or powder that might be causing inconsistent hammer thrust. Cheap things to check before pulling that barrel. I'd do these if LOTS of Boretech Eliminator and cleaning the throat with J.B. doesn't work. THEN, I'd yank it.