Home Forums Hunting & Shooting AR and Tactical Rifles DPMS AR15 DCM Barrel Problems

I recently purchased a 1X8 Stainless DCM Barrel from DPMS. 278 rounds have been fired. My goal was to shoot 69 grain and 77 grain Sierra HPBT bullets thru "The Course". None of the previously loaded ammunition 24.4 grains of IMR4895/69 Sierra, would function thru the new barrel. The extractor would tear off the rim, leaving the case in the chamber, which would require a cleaning rod for removal. They were not difficult to remove,with a rod. I thought, better reduce the loads and try again I got down to 22.5 grains of IMR4895/69 Sierra, and still tearing off the rims, by the way Sierra's min load listed is 22.9 with a velocity of 2500. My loads were proudcing 2788 fps/33ES. Today, I called DPMS, and talked with Shane, the first thing out of his mouth, is "WE don't warranty any of our products, which has used reloaded ammuntion". This is standard with most arms manufacturers, however, and I pointed out to DPMS, the only way to shoot these matches is with reloads. It will be interesting to see what they do, and I will let you all know, what there suggestion is as to solving this problem.

Jerry

Change powder To Hodgdon 4895. Some of the old IMR was hotter than hell.

None of the 4895 is worth a flip in an AR in 223. Stay away from it, it'll give you slow but accurate loads when you get it right which basically sucks in XC shooting.

69/77s Head for Varget for starters. RL15 is another failsafe. 25 ish grains for 69, a bit less for 77s. Those would be top loads. Ramshot TAC if you want ball powder that works great.

Never could figure why folks wanted to mess with 4895 there in the 223.

ALSO the rims coming off... that is also a sign of a large gas port. It may end up being somethign you have to live with and you may need to get a legal but adjustabel gas tube. Idiots mass building these guns dont' understand non metered gas systems... they put in the same size port called for in specs that started with the 55 ball rounds in the 60s.... taht is not the correct size for heavy competition bullets....

Good luck, Jeff

BTW, shoot some federal 69 Gold Medal in that gun or even 77s gold medal, my bets are it'll rip the rims also...

Idiots that run those shops... they should contact the stupid idiots at Fulton Armory so they can both whine about reloads...[bleep].

Jeff

Hi Jerry;

I own two of the DPMS barrels(BL-DCM) as sold by Midway #550750with the adjustable front sight tower and have installed several of them on club members AR's dating back to mid 05 to date. In fact I just received five more last week. Installed one Friday evening and took it to the range for zeroing the front sight tower today. Never a problem with any of them! Accuracy has been extremely good and no malfunctions.
Keep in mind that this particular DPMS barrel is marked and chambered .223 Rem. meaning it has a SAAMI spec chamber.

I totally respect Jeff's advice as I have known him for several years and shot with him at Camp Perry. However I would suggest you consider that something is wrong with your brass.

I can relate to your problem, to an incident that happened to a a deer hunting friend of mine about 35 years ago. I'm not saying that you may have done this but my friend used a liquid brass cleaner. He was very knowledgeable and picky hand loader. After cleaning his brass, he got in a hurry to get them loaded so he placed them in his wife's oven to dry them. The temp setting and the length of time in the oven annealed the whole case. Result was the same as your problem. The cases expanded upon firing and the rims were too soft. The the extractor in his Winchester Model 70 pulled the rim off leaving the case stuck in the chamber. He packed up his rifle and headed on down to the local gunsmith to have the stuck case removed. The smith removed it with a cleaning rod. As my friend explained his reloading practices to the smith, he suggest he throw away his brass because he had annealed the cases, rims included.

Some of my favorite loads in my AR's (the DPMS barrel included) are as follows. Please work up to these loads as I would consider them to be max:

Special note:
All LC brass resized to SAAMI spec's (per Forster cartridge case gage)through a RCBS FL die. Trimmed to 1.750"

69 gr. Sierra Matchking seated to O.A.L. 2.245"
24.5 gr. H-4895
Federal 205M primers
Avg. velocity = 2788 f.p.s.

69 gr. Sierra MK seated to 2.245"
25.0 gr. RE-15
Federal 205M primer
Avg. velocity = 2769 f.p.s.

80 gr. Sierra MK seated to 2.405" (SAAMI Spec. chamber!)
24.6 gr. RE-15
Federal 205M primers
Avg. velocity = 2718 f.p.s.

77 gr. Sierra MK O.A.L. 2.245"
24.5 gr. Varget
Rem. 7 1/2 BR primer
Avg. Velocity = 2702 f.p.s.

60gr.Sierra H.P.#1375 oal=2.245" Great reduced course load!
24.6 gr. IMR-4895 (surplus) pull down powder
Rem. 7 1/2 BR primer

I would hope I could be of some help.

Regards:

Dave McGrath
P-100, Distinguished Rifleman
Match Director E.M.S.C.
Life Member NRA

Hey Dave

Great to see you here!!

4895 works for some, I've seen that. But seems like its finicky on barrels vs pressures... IE you should be easily scaring 2900 with a 69.

Usually rim lifts are not brass, but are simply too much pressure, but VERY often a large gas port for some reason. Choke that gas flow off somehow, and burning rates of powder can affect how quickly the system opens or attempts to open, hence a change of powder suggestion.

Hope you are doing well, and hope Kathy is too!(did I get the Mrs right? Memory fades at times...) Almost intended to try Perry in 2008 but a double elk hunt popped up... so I'm more than likely off to CO and then NM...

Jeff

Hi Jeff;
Yes you got the Mrs. name correct. Chris put me onto this site because the fella was having some trouble with his DPMS barrel.
Hey this is really a great site. Covers about all there is to care about!
Lost your email address in a hard drive crash. Actually had two of them in 11 months. Here it is mine. davear15yahoo.com
Take care!

Dave Mc

Dave

Once you start, you really post up a storm.

Welcome.

Thanks for the replies:

I kind of kept the initial post somewhat short, for space's sake, thats why I didn't mention Varget, or RL15. I tried them as well. RL 15, did not give me any accuracy, 2" @100 yds, still tearing some rims off. Varget shows some potential with 77 Grain Sierra's, but I had so much trouble with every other load I tried, I gave up on it for now. As to the brass, it is all once fired Winchester commercial brass, that had been sized trimmed, and had the primer pockets cleaned before loading. In my opinion cases were never a consideration, and OAL was ignored too! Remember only 278 rounds were fired. The reason for IMR4895, it really shot lights out in one of my other AR'S, so I thought I would try it in this barrel. Also, a lot of the "old" guys here shoot 4895 in everything, and they love it. I am not set on any one powder. Once we get the rim thing fixed, I will choose the powder that gives me the best accuracy. I sent the whole upper back to DPMS, and we shall see what they come up with. Dave, at DPMS mentioned it could be a gas port problem. I don't know if they will fix it, how could they? Send it back to me and tell me where to put the barrel, LOL, or install, or sell me an adjustable tube, as was suggested. We'll see.


Jerry

Here's a couple more examples, from my notes. Dave your load of 22.5 grains of H4895 gave you 2788fps, my load of 22.5 grains of IMR4895, gave me the same velocity. That's 2 grains less powder. I tried 21.5 grains of Varget got 2510fps, with a 77 Sierra, @ 300 yards, even though I was mad as heck, I managed to hold 9's and 10's with this load. Next time I had some rims tear off.

Jerry

If the rims come off with different powders, 4895 is not the culprit.

Too large a gas port for sure. They may tell you to shove it though..... depends...

One last thing I"d do, get some more brand new brass... maybe say RP (WIN can be soft at times) and just try a few rounds to see.... eliminate the brass issue before going furhter.

I had an Oly SUM barrel do the same thing and it took them 10 years to send a new tube, first time they said no way, I got hold of a PR guy 10 years later that replaced it!!

Jeff

Hi Jerry;
If in fact DPMS's contracted barrel shop did put too large of a gas port in the barrel, you could move the front sight tower forward about .010" to .020" to choke off the gas port somewhat. That is if you have the set screw adjustable front sight tower.

Question. Was this a complete upper from DPMS or just a barrel purchase?

On the rim problem, I honestly think that if one case dosen't get it's rim tore off and another one does, it would indicated a brass problem. I think I would have tried some LC brass before I sent the upper back. Try to stay away from Winchester brass and especially Federal! I only use (LC) Lake City brass before Federal's take over of the plant in 2002.

On my suggested loads I think you misread my powder charge on the H-4895. I use 24.5 gr. with my 69's.

Jerry, keep us updated on your problem.

Regards,
Dave McGrath

One other thing Jerry. Trimming your brass back to 1.750" is a good practice to stay out of trouble and to insure square case mouths leading to better accuracy. You could have your cases too long, flowing brass into the rifling upon firing leading to pressure and extracting problems.
Remember, you have a "new" barrel with a SAAMI spec chamber. It is shorter than the Wylde or the others. If your brass is into the rifling, there's your problem!

Regards,
Dave McGrath

Dave: It was a typo, when I was comparing your H4895 load to my IMR4895 load. Your load was 24.5 and mine 22.5. All the brass was trimmed to 1.750, as suggested by RCBS before loading. I just purchased the barrel, and yes it does have the adjustable front sight. Dave at DPMS asked me to send the whole upper to them, so that is what I did. Here's another interesting thing about this barrel, I tried some other loaded ammo which I use in other 223's I own, and had the same result. A 52 Grain Hornady match bullet with 24.8 grains of IMR4831 also pulled the rims off. In 2 other 223's no problem at all. Also a 50 grain Sierra Blitz with H335, don't remember the powder charge, tore the rims also. I use Winchester, (Law enforcement) brass in other AR'S, with no problems. I think I have received a POS barrel. I have tons of experience loading and shooting 223's, as well as numerous other calibers, but I haven't run into this problem before. And I can tell you, if there is a problem, or a screw up, that one can make, I guarantee I have made them all, LOL!

Jerry

ya know, it could also be a bad chamber... I'd expect the gas port still, but chamber, especially off center weird chamber could hold the brass long enough to rip the rims...

Jeff

Thanks to all.

I will post again as soon as I hear from DPMS. If they won't do anything for me, I will throw the barrel away, put on another and let all the shooters in Arizona know about it.

Regards:

Jerry

Customer service is the big thing in the end really! I know of that other bunch of idiots, FA, that probably would be acting the same way too.

Jeff

I'll second what Dave said about trimming brass. I have seen guns chambered with reamers that would cause pressure problems if you didn't trim the brass.

Also you should try a Tubb CWS. The extra mass in the bolt carrier can do wonders for an overgassed gun.

YMMV

B

BPM

WOW I had forgotten about weight!!! I've not shot in a bit now... You are dead on about weight issues and overgas!!! An old M16 bolt might be enough to help too..

FWIW I've yet to run into a chamber that non trimmed brass would hurt, but then the way I size my brass, with neck bushings, it really doesn't grow like using and expander would.

Thanks for the input, Jeff

Well, here's the news from DPMS, they think I need a new extractor, I mentioned that I had just recently changed the extractor and spring, but, they said that is what their gunsmith had determined, also he, the gunsmith, "noted" the carrier and bolt were "NOT" DPMS. I asked Shane, if they had fired my upper, he hemed and hawed, and said the gunsmith determined, it need a new extractor, etc. I can guarantee you it did not. They don't want to do anything to help me out. So you guys better beware. I can tell you we bought a BUSHMASTER DCM rifle, and it works great, and is a tack driver .5 GROUPS, @ 100 yds. Back to my issue. I have determined, when I receive the upper back, I will remove the gas tube, and go to the range and shoot some groups. If I can easily remove the fired cases from the chamber with the charging handel, then I will install an adjustable gas tube. If not, I am going to remove the barrel, and send it back to DPMS, with a nice note, that they can keep it, and the money I paid for it, and I will move on from there. I didn't want a freakin project, I just wanted a twist to handel heavy bullets, I am disgusted.

Jerry