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

Jerry

Do you have another upper"? IE bolt? Swap carriers and see if it extracts. I have swapped extractors a number of times in some rifles, but thats never been the problem, save one time.

I really doubt its the extractor also. But one never knows.

Let us know how the test goes, Its always educational to see it out to the end if you can.

Jeff

Jerry,

I think you will have more luck with a CWS. Next match you go to ask around and I bet someone will break open their rifle and let you try it. The thing is easier to swap out than pulling a bolt carrier out and you won't have to pull the front sight and goof up your zero. If your lucky they will have both the weights you can try.

In my experience, most of the time that they rip the rims off, it means the gun is over gassed and no extractor swapping in the world will fix that. Sorry you got the run around from them. It's par for the course for most all of the places you can buy stuff.

B

bpm990d:

Thanks for the advice. I am not familiar with the CWS, can you give me a little more info. As I mentioned earlier, if the barrel is accurate, which it has shown at times, and I can get it regulated some how, I will keep and shoot it, although with a bad taste in my mouth for DPMS. And I guess I will have earned quite a lot of experience, while not exactly what I had in mind, not all bad.

Thanks

Jerry

It's just a metal tube with two flanges. The one at the top rests against the end of the bolt carrier, and the one at the bottom allows one of the two weight to be secured in it. It just slips into it and is held in place by the buffer tube. It's pretty simple. My AR is overgassed and I have the heavy weight in it. The brass use to come out with some rim lifts, but now it's perfect. I bet someone has one in their gun where you shoot and will let you try it.

B

bpm990d:
Thanks for your imput I looked it up with the link you sent. If my tests work out, once I removethe gas tube, then I will go to your suggestion.

Thanx

Jerry

Carrier weights have been made too... Just google Tubb Carrier Weight system, it might show a photo.... M16 carrier as suggested earlier could be enough additional weight if you have access.... I run them in a few NTIT uppers for a reason...

Jeff

Jerry;
I for one am not happy with the service you got.
Okay, put on another extractor and try that. I seriously doubt that is the problem but do it anyway. Why didn't they do it and try it? Never test fired it, WRONG! Then to say it wasn't a DPMS bolt and carrier, OH BOY!
Do try firing it without the gas tube and see what happens.
If you find no problem extracting fired rounds with the charging handle, then move the front sight tower forward about .010" to choke off some of the gas. I still don't think that you have too large gas port. If you have a numbered drill set, move the tower forward on the barrel and measure it.
All in all though, it is plain to see that their customer service stinks! I have never had a problem with them but I have only bought several barrels with their name on them for my friends and myself. They may have different shops doing their barrel work but as for me, their barrels have been great, no problems or issues!
As for their other parts, I don't care for their triggers, they suck almost as bad as a standard GI and their rear sights are all cocked to the left just like the gun show/shotgun news vendors. These are not nit picking issues when it comes to NM competition rifles. Those are the only AR's I deal with. That is why I say go with RRA.
Keep me posted. I'm really interested in your problem. If it is their problem, I'll take your word as being honest and believe me, I'll beat my keyboard to death on their service. Ha, never even test fired the rifle. Their going to pay for that one!

Dave McGrath

Jerry;
I'm still not done posting. Had to eat dinner and got in a hurry.

In fact, I'm a little upset over what I read here today. This isn't a problem dealing with rocket science. Hell, it's a simple AR!

Now, in any small shop or in the case of "DPMS" the way to handle this whole problem would be first to check out the assembly of the upper. Then exam the parts. If, as their smith says, the extractor is broken, they should have replaced it and test fired it. Then sent it back stating so, to included the words "have a nice day"! Thanks for buying our product! That's my opinion and that's the way any business should have handled your problem.

In my experience I have seen about every type bolt carrier there is for an A2 upper and have used them on many A2 barrel/bolt combos. Never have I come across a problem needing a carrier weight. Now if you were shooting a space gun with a 24 inch barrel with the gas port at the same location as an A2, then maybe you need a carrier weight. However your light loads with the medium burning rate powders that you are using, there shouldn't be any problem with the carrier regardless of the barrel length.

Through my dealings with AR shops over the past 14-15 years, I know of a few trusted shooting friends, as to how badly they were treated and even talked too over the phone. I will not give those shops "any" endorsements on the range or on the internet shooting forums (believe me, I get around and I'm not bashful, note my name is attached to all of my posts) until a time when they have taken care of past service problems and apologies are given. That's just good business and the customer is always right. Sometimes a business owner or customer rep has to grit his teeth but it pays off in the long run!

Again, keep us informed. Good luck!

Dave McGrath

Dave:

Thanks for the kind words. I don't think I have been asking DPMS for anything more than to help me make "THEIR" part work properly. As I said, if it dosen't work out, I will send it back to them, and they can keep the money I paid for it. Then we can let all the AR shooters know what DPMS' stand is in regards to us. Shane talking about a new extractor, what a crock. The barrel has only had 278 rounds thru it, and I already replaced the extractor and spring half way thru all that shooting. These type of things should not happen, and just because I reload, dosen't mean I am ignorant, or inexperienced.

I'll let you know how it works out.

Thanks Again

Jerry

Jerry;
Try some factory rounds and a few of another shooter's rounds too. Just to totally rule out anything DPMS could screw with you on, borrow/try a different carrier too. They blew you off for reasons like "It's not a DPMS carrier or bolt" or it's a bad extractor. How long have they had it now to make that decision?
I would think it is possible that an extractor could go bad or you could have bought one a bit out of spec but change it out with a friends or buy a new one from RRA. Ha, here you go, tell them you will BUY one of their's since yours is at "fault"!
If they still have the upper, it would be in their best interest to at least try to help you out! A minor problem, which I'm sure it is, should be delt with professionally. After all, DPMS smith's are "professionals", right?
Wish I could help you out. Sorry we are many miles apart.

Dave McGrath

Jerry;
Try some factory rounds and a few of another shooter's rounds too. Just to totally rule out anything DPMS could screw with you on, borrow/try a different carrier too. They blew you off for reasons like "It's not a DPMS carrier or bolt" or it's a bad extractor. How long have they had it now to make that decision?
I would think it is possible that an extractor could go bad or you could have bought one a bit out of spec but change it out with a friends or buy a new one from RRA. Ha, here you go, tell them you will BUY one of their's since yours is at "fault"!
If they still have the upper, it would be in their best interest to at least try to help you out! A minor problem, which I'm sure it is, should be delt with professionally. After all, DPMS smith's are "professionals", right?
Wish I could help you out. Sorry we are many miles apart.

Dave McGrath

Jerry/Dave

An extractor CAN go bad in one shot. Though its very rare. For the issues you are having, replace it with new, but don't toss the old one. If the problem is solved, toss the old one, but if the same, then both extractors are good.

It takes just one bad stuck case, and an extractor not quite in spec or hardened enough to roll the edge.

I'm still different that you on the gas though Dave. I've seen it in more than one gun that a weight has solved issues. Just had not recalled that when this thread started.

Companies, RRA included, that are mass producers/sellers of AR barrels always go large ports, just to be on the safe side. By large I mean spec ports or larger if you are accuracy speaks.... Thats the wrong way to look at it IMHO. We aren't shooting ball 55s that much anymore.

Jeff

Jeff;
We need to establish what diameter a gas port should be, then go from there. Meaning what is industry standard and what is custom for those that use exotic powders like VV540 etc.. Jerry is using common medium burning rate powders and light loads. If he were to have any problem, he should have less port pressure with his loads causing short stroking.
Jerry's problem was common in the M1 rifle when a hand loader used a case full of slow burning powders like 4831 or 4350 which also wrecked the op-rod.
Now I have seen different type bolt carriers when changing barrels. The barrels I have used came from Wilson, Douglas and Kreiger machined by WOA, CLE, RRA, DPMS and a couple other clone dealers such as Sherluk and M&A. Some carriers have more "meat" on them making them heavier but none, not a single one ever came back with a problem. Most shooters I know including myself use 4895, Varget or RE-15. Some like ball powders from TAC or Hodgdon like H-335. An industry "standard" gas port diameter, whatever that may be, will not cause a problem such as Jerry's "unless" in fact the shop that made Jerry's barrel deviated from standard for whatever reason. If that is the case, rest assured, there are many barrels that will also have this problem. If that is the case DPMS needs to take that up with their supplier and make good on it rather than dance around an issue that will hurt them bad in sales now and forever more! After all, their name is on it and if they don't make good on it, shame on them!

On weighted bolt carriers. I know they exist. They are best suited for the non custom longer barreled AR space guns with the gas port the same diameter and in the same location as an A2 barrel. On a 24" space gun/varmint barrel, the bullet hasn't exited the barrel before the bolt has come out of battery causing problems. The heavier carrier slows the action enough until the bullet has cleared the muzzle. These weighted carriers on A2 rifles, IMHO are simply another "gimmick" like molly coated bullets that Tubb endorsed, collecting royalties. Fact is, these "gimmicks" won't hurt you but did you really need it? After many bought into them, most came to realize they didn't!

Lets see what DPMS does for Jerry. I honestly believe Jerry will give them a fair shake by trying anothers ammo, purchase a extractor from DPMS, since they said he needed one, that way they can select a "good one" for him and if all that fails, try another bolt carrier from another rifle.
I wish he were local, I would love to tackle this problem and deal with DPMS first hand, especially after the way he was treated over the phone. Well so far that is!
Ha! They didn't even test fire his rifle. I can't get over that fact since he was told to send his upper to them! Wow, that's one for the record!

Dave McGrath

Dave,

Irregardless if the rifle is a Match Rifle or a Service Rifle; they are not a gimmick if the gun is overgassed. It's an easy way to increase the dwell time of the bolt carrier. It can be adjusted by simply adding or removing weights and it is a lot easier to test it to see if it works than replacing the gas tube with an adjustable one or venting the gas tube.

B

Derrick espoused the use of 090 or 099 IIRC... which is over the old standard.... there is no standard that I'm aware of.

My ports are whatever John uses, knowing that I shoot 69-90s. It runs fine with 52s though too.... Point is rethinking the port size might help, but still afraid that companies are more worried about function than brass life. As most are just weekend blasters.

You know I don't shoot N540 much..... I generally shoot a generic WC852 ball powder, Pats in OH, 200 pound keg.... So I'm working with smaller ports and "standard" powder about 90% of my shots.

Jeff

Got the upper back today, with a letter explaining, it's not their bolt, or carrier, and it needs a new extractor. The extractor, I guarantee is ok. I will pull the tube, go to the range, and let you know the results.

Thanks

Jerry

Jerry;
Thanks for keeping us posted. I can't get over the poor service you got from DPMS. Anyway, it seems to be the norm from the AR folks today execpt for RRA.
If it needed an extractor, why didn't they "sell" you a DPMS extractor? I'll bet there is a difference in extractors too not being "their's"! Why did they tell you to send them the upper? Why didn't they install a DPMS extractor and test fire it? These are the questions I would have asked.
Having said it's not their bolt and carrier is being chicken $hit!

Dave McGrath

I can't answer the questions you guys have asked in regards to DPMS, but I have a couple more facts and thoughts, that will add to the conondrum. This morning, I removed the gastube, and fired "ONE" shot out in the backyard. The case was easily removed from the chamber with the operating handel. Also the primer was dented in, not flat. Not much of a test, but something. Also when I went to run a patch down the barrel, it came out pretty dirty, I was surprised, because when I sent it to DPMS, it was perfectly clean. Did they in fact shoot it? Also it is much cooler here now, than in August and September, another thought, LOL! I'll shoot it some more and keep you all posted.


Jerry

Bolt carrier weight or adjustable gas tube. Your port is too big....

What powder were you shooting when it was hot? 4895 IIRC, but it was not a warm load either... had it been 2520 or 748 I'd might agree temp has something to do with it.... In the future if you are uncertain if its temps, just ice your ammo down and shoot it cool, if fine, then its just a temp thing, and too hot of a load for the temps...
Varget is SUPER forgiving in that area, and easy to dump charge with...

Jeff

Hey Guys:

I finally talked with someone at DPMS, Dillon, who wanted to help me out. Now what they did was, they removed my bolt and carrier, and shot the rifle with their bolt and carrier, and 55 grain mil spec loads. Now how in the world they determined I needed a new extractor, is beyond me, I guess when the upper functioned with their mil loads and carrier assm., they just GUESSED, my extractor was bad. After some discussion he admitted I might be over gassed. So I just ordered an adjustable gas tube,and I will continue this saga, once I receive it. Also I was using IMR4895 with the 69's, and Varget with the 77's, and none of the loads are near max.I am just about wornout for all this, but I appreciate all of your input and help.

Thanks

Jerry

Jerry,

What is the diameter of the gas port on your barrel?

I know what mine are on both new and used take off barrels from various manufactures that I have on hand. This is another rabbit I failed to flush on this thread.

As I said previously on this thread I own and have installed several DPMS barrels without a problem. Another upper I will assemble on Friday.
You have talked to several DPMS reps and they told you to change the extractor. Unknown before your last post, they did test fire the rifle with their ammo along with another bolt/extractor. It functioned. As it all turns out now, they have been more than fair. After all, the only component that is their's is the barrel. Now you have over 200 rounds fired. If you were "over gassed" you would have over 200 cases with the rims pulled off!

Instead of taking their advice, several others suggestions or a number of things I suggested, you just ordered an adjustable gas tube.

Best of luck;

Dave McGrath

Here's the latest. Today is 11/24/2007.Went dove hunting this morning and took the AR with me to just shoot a box of ammo, and see what would happen. It functioned all 20, without a hitch. Yesterday, while dove hunting I fired 6 rounds without the gas tube, and they were easy to extract, so at the urging of my friend, I reinstalled the gas tube to try as a test. What scares me, is it the cooler temperatures, or some unknow work DPMS did while they had it. I guess I'll just keep shooting it and hope for the best.

Jerry

Cooler temps will cut down on gas flow.

As great a friends as Dave and I are... you are still overgassed...

I Re-barreled another AR for a club member on Friday with a DPMS barrel (BL-DCM from Midway USA item number 550-750). Shot it on Saturday for break-in and zeroing the adjustable front sight tower. Again, no problems!
That makes 10 or 11 that I have done without any problems and I know a dealer/smith about 40 miles from me that has done several others with the same barrel, all without a problem. Very accurate barrels I may add too! No copper fouling either!

Jerry, your gas port diameter should be .0995" which is a #39 drill. I have new barrels in my shop and several shot out take offs from RRA etc. and this seems to be the industry standard diameter. I'm sure the take off's have all seen their day with different weight bullets, powders, extreme barrel temps on hot days during "rattle battle" competition etc.

Here in Pa. we shoot high power when there is snow on the ground to temps in the high 90's. May not be as hot as what you and Jeff encounter but I know of no AR problems relating to "over gassed" or rims pulled off the cartridge cases.

Hope everyone had a nice Thanksgiving.

I don't know what else to say. Ya'll take care!

Dave McGrath

Dave:

I didn't take DPMS' advice about the extractor, because it was a crook of S---. As I mentioned earlier, I had changed the extractor during all of my previous testing, and didn't believe that was the problem. First of all if DPMS would have told me the FIRST time, what the had discovered, I would have told you all about it then. Telling me after the fact, just created another waste of time and effort. The extractor must be ok, as it pulled all 27 rounds out of the rifle this weekend, just as it is designed to do. As a matter of fact one of the guys who observed me shooting the 20 rounds, mentioned they 'sounded" KIND OF LIGHT. 24.5 GRAINS OF imr4895/69 SIERRA hpbt IS A "LIGHT" LOAD, In fact under min, in the Sierra book. I ordered the adjustable gas tube, as a way to insure I could use the barrel, without any worries, I hope. I have not removed the front sight to check the port size, as I locktited the set screws, and didn't as yet want to lose my front sight zero. I'll let you know how it goes. And thanks a lot for your help and advice.

Jerry

Dave

Have seen that standard size show rim lifts with charges of RL15 that in another barrel and smaller port would show nothing....

My episode of gas ports an the AR started circa 1990 with standard port size 995 in Oly barrels, I'm leary of it ever since. For 55s probably ok, but heavy bullets, 75 and 80s at that point, and different powders, it did not work well at all.

Jeff

I think a lot of the problems I have been having, are my "LACK" of experience with the AR. My impression was, bolt it on and go shoot. I didn't expect a problem, and no one out here mentioned gas port size, as Dave and Jeff had, until I talked with John Martin, father of Derrick, and a good friend of mine. He told me of guys that were "plugging the gas hole, and then redrilling to a smaller size. Dave the barrel is accurate, lots of groups under 1" @ 100 yds, that is/was not my complaint. If it only tore off one rim in 4, how could I shoot across the course with that performance. Nevertheless, if regulating the gas solves the problem, I will call Dillion back @ DPMS, and report to him, as he asked me to do, his idea, if one guy, me, runs into this problem, at least they will have enough info to help another out.

Jerry

Derrick Martin saying a smaller port??? Wow, I was almost sure he was one that said go larger if anything... I also thought in reading all his articles/books, that he came upon pressure signs sooner than normal on loads generallys peaking and I always attributed that to big gas ports for him.

Problem with smaller gas ports is sometimes the guns don't run 100% till they are shot and broken in some. Heck my custom M14 didn't run right for a couple hundred rounds, but it was tightly built and needed to break in.

You cannot afford one failure in match shooting. I hate alibis anyway....

Dave knows enough about XC shooting, he's an icon at Perry and always has been since I can recall. His wife volunteers there too!

Jeff

Jeff:

Derrick didn't suggest I plug the gas hole and redrill, his dad did. If you know John, or know about him, you know he is a high master, and in his time, was really tough to beat. Of course he prefers the M-1 and the M-14. He comes over to my home, and coaches me, on position, trigger pull, timming etc. and I am 62. John is only 79, lol. I still feel like I am pissin in the wind, and dang it, that barrel should work without all this messin around. Don't you all agree?

Jerry

I agree on the barrel

What I found hard to believe is that Derrick IIRC, is a proponent of more gas... Interesting to see his dad take an opposite view.

I don't know John, I do know Derrick a bit though. Both being HMs, and I'm HM from service rifle only in both XC and LR.

Be glad ya got a coach of that caliber!

Jeff

Jeff: I am real glad Ol John is close by. He is an asset to all shooters, and his goal is to promote more shooting. I received the adjustable gas tube last night, I am going to load a few of the cartridges, which "always" tore the rims, and go shoot it. I bet it will work fine. I'll let you all know.

Thanks again, and Merry Christmas.

Jerry

Jerry,
The best money I ever spent was a book called BLACK MAGIC by John Feamster. He likes H335 and 52 Sierras for close range.
FWIW I shoot 77's at close range and 80's at 600. Varget works for me. I have an Olympic Arms barrel on my DPMS gun and it has never malfunctioned in 10 years. They give us barrels to put on the junior shooters guns and have donated rifles to our State Team to take to Perry. DPMS is OK in my book.
My instinct tells me that if you mix and match parts from different manufacturers you could experience tolerance stacking which will not help anything.
I currently earn a living as a machine shop inspector, and I can tell you that whatever can go wrong will go wrong at some point.
Good Luck.
whelennut

Whelen

One of my favorite books.... wonder why ... grins....

Jeff

Next to the 270 Winchester, the 35 Whelen is my favorite. I have killed many critters with both, for elk to rabbits. Interesting, that both of these cartridges are based on the 30-06. I also have 6mm-06, and a 6.5mm-06, oh yeah a 338-06 as well.

As to the AR, now that I have the adjustable gas tube, and DPMS has had their chance to look at the upper. The only report I can now give, is after I go to the range, and run the loads over a chronograph. I somehow have the feeling,that the velocties will be lower than when I started out, that resulting in no rim tear offs. The original problem could have been a short throat, large gas port etc., but I can guarantee it was not the extractor, or head space.

I'll let you all know soon.

Jerry

Jerry,
I was digging through my loading manuals last night and was reminded that there have been three different chamber variations in recent times. I would guess that you have a 223
Remington chamber but it could be the NATO chamber?
That might make a difference. I have a 1/7 twist and assumed that I was good to go with the 80 gr Sierra's but found out that I need to have a special chamber with a different leade angle
into the rifling. (very frusrating)
I also share your frustration that a person can't just go buy an out of the box rifle for competition. You need to replace the trigger and sights in most cases. More than likely the factory barrel is not acceptable either. A sad state of affairs and tough on a new shooter or an M1A shooter swithing over to the "dark side" Why can't it be simple?
whelennut

Whelennut:

You'r right, why can't we just buy one out of the box, well maybe we can. Bushmaster's DCM rifle, is as accurate out of the box, as I have seen. Excellent trigger too! Bench testing the bushmaster, with the loads I have been having all the trouble with, gave groups under.75" @ 100 yds. That's the kind of accuracy, I want to start with, and build from there. I am a "freak" about shooting groups with differnt ammo, before I go to shoot a match. Probably too darn anal for my own good. The guys that I shoot acroos the course with, say go load this load, or that one, and go shoot. I realize there are certain loads that "everybody" shoots and has success with, but my regimen, is work up loads, even if I reach the same conclusion as everyone else. It's part of my fun. I spend a great deal of time shooting form the "bench", with all sorts of different rifles and cartridges, and this is the first time, I have not been able to solve the problem, so far, myself.

Whelen

RRA comes factory ready with a much better trigger than a bushy will ever dream of having...

Jerry

Shoot it with the new tube yet?

The old days you had to swap all parts, these days they come match ready!
Of course I remember issues with new M14s years back too!

Jeff

Jeff,
Some of the guys around here had good luck with out of the box Armalite if I remember right. I bought a DPMS because I was on a buy local kick a few years back. Now I say buy the best you can find no matter where it was assembled! (If you want to win)
I am giving up on post front sights and want to build a match rifle on the AR-10 platform with a .260 barrel. Once I tried match rifle sights and a match rifle trigger............
whelennut

Yep, I've heard same on match sights.... I've shot them a few times... I could really get used to them. I'm 42 with some P100 tabs etc..... but not shooting since 03. Not sure what will happen though I'm on a mission to shoot a 200 at 1000 with the AR service rifle.... that means a special build and post sights again... I doubt I'll shoot XC ever seriously again. But that 1000 yard mark is tempting!!! Once I learned how to shoot 200s at 600 the 1000 became the next logical goal!

You'll like the 260 I suspect.

Jeff

Finally, today 12/6, I got to the range, and had a chance to shoot some groups, and run the ammo over the chronograph. Here's the results: last year,and before I sent the upper to DPMS, I shot 22.5 grains of IMR4895/69 Sierra, and got 2788 fps, Extreme spread 31, today same load 2641fps/43es. 23.5 grains last year 2895fps/75 es, today 2817fps/53es. 24 grains gave me 2911fps/95es, sierra says 24.5 grains should give 2700, and 21.5 grains of Varget, with a Sierra 77 grain, last year 2510fps/18es, this year 2444fps/57es. All of this means nothing however, if the gun won't work. I ran 33 rounds thru the gun today, and 32 worked fine. I did have one rim tear off, and thats when I quit. The load was 22.5IMR4895/69 Sierra.I can attribute the little bit of lower velocity to the ambient temperature, so that is not a concern. Here's where I got the rim tear off, after shooting about 28 or 9 rounds, I noticed the action appeared to be moving a little slow, so I opened the gas tube up an 1/8th of a turn, I started at 1.5 turns as was suggested by the mfg., within the next 4 or 5 rounds I had the rim tear off. Also to note, the rim was torn clear down to the extractor groove, and was the width of the extractor, so much for a bad extractor. I really wish I had'nt increased the gas flow, as I would have liked to shoot a few more rounds. I really am trying to to be fair here, but I am almost sure, I have a bad barrel. All this "screwin" around should not be necessary. If it works thur another 100 rounds, after I readjust the gas tube, and it will group, I will use it next season, if not DPMS can have it, if they think it is so great, I will donate it to them, and they can sell it to someone else, LOL!

Jerry

Jerry

Have you run LC brass and same loads through yet?

Though it sure seems gas flow is an issue, it may be related to a bad chamber, requiring so much gas flow to extract the fired brass...

Have you spun loaded brass, at about 3 points on the case, IE neck, just in front of the base, and mid case, on a dial indicator and then after firing to "check the chamber" dimensions?

Or could it be a tiny bit of crooked die, creating a "bent" round before firing?

I don't recall if you tried factory ammo or not.

Keep us updated.

Jeff

Jeff:

Thanks for your response. As to the ammo, all I can say, is it works in EVERYONE else' AR'S not mine. According to DPMS the chamber etc. is to spec! I've about had it, and I really wish I had the success Dave has had. I'll do a case run out, I haven't done that yet. I will note as well, that most of the cases are pretty dirty after firing. Back to the range for one last time.

Jerry

Jerry,
You are shooting a lot lighter load than I am. I am loading 24.5 grs Varget with 77's. If it was me I would send them the rifle and tell them, to send it back when it works!
An extractor has to be less than the cost of shipping the rifle?
I am confused.
I don't know who makes their barrels now, but when I ordered my 1/7 twist it had to come from Olympic Arms and it took a few months. Maybe you could contact them and see what size gas port they use? Mine has always worked perfectly, with no adjustable gas tube or carrier weights required. I guess I was lucky.
I guess if I were having that many problems I would sell it and get a new Bushmaster or Rock River gun. You need to be working on the positions and not fooling around with adjustable weights and gas tubes IMHO. I think Jeff is probably right, you could be over gassed. I don't like to badmouth anybody's products because anyone can have a bad day, but I remember replacing an extractor in a customers rifle and the new one was no good either. I repeated this several times until the owner of the shop got PO'd.
I ended up calling the company and they admitted they had a batch of extractors with bad heat treatment. They sent me a new bag free. I had a few hours of labor down the tubes and a irate boss by then. I would imagine barrel makers have bad days once in awhile too!
Good Luck!
whelennut

Whelen

I dont think you are lucky, I think Jerry is unlucky. Happens to everyone at some point. First shot with my very first Zeiss scope in the 80s, something broke loose and rattled around, but they fixed it!

Thats the real point, repair the dmn gun right.

Jeff

Whelen:
Yeah, my loads are light, that's the only way I thought I could get this "thing" to work. You are right on about, screwiing around with equipment, when I should be practicing postions, timing, etc. No match has ever been won by equipment first, it is always the riflemans skill, then equipment. Reminds me of the guy, who has to have ever new fangeled thing that comes along in "any" shooting game. He spends more time with all the state of the art stuff, then he does with his skills, and wonders why he never wins. I am old enough now, where the young "turks" are going to shoot better scores than me anyway, but I still wish to be competitive with my peers. Also, the extractor is NOT the problem, and I only bought the barrel from DPMS. The rifle is an Olympic Arms, and I never had a problem till I changed barrels. One more shot at the range, if things don't work out with the lower gas setting, I will put the old barrel back on,and quit screwing around. I won't allow the DPMS barrel to be used by anyone else if it dosen't work, and I may take all your advice, and buy a new rifle. BTW, I have learned a lot from you guys during this thread, thanks.


Jerry

Jerry

I"d been biting my tongue as I don't shoot much at all anymore. But the wife and I used to almost sleep with our ARs, you can ask Chris F or Dave about that.

I'd love to have that barrel if you give up on it. I don't have much spare change laying around, and I"m not sure when I'd have time to monkey with it, but I"d love to have it just to see what it would take to get it running right, if possible or what the real issue would be why it won't. THats the way I learn things, just by playing with them.

If interested PM me if you'd like.

Jeff

Jerry,
Friendly advice time.
If I were you I would get to know some of the guys who have gone distinguished in your area recently, and ask them who put together their rifles. Have them put an upper together for you. It will be cheaper in the long run!
Your eyes aren't going to get any better as you get older.
Get to shooting!
whelennut

You are close enough... White Oak Precision.... builds match winners all the time.

Jeff

I'll make it a bit easier for you...there are three distinguished shooters that I know of on this thread (four if you count Rost's wife!). Two of the three recommend White Oak without reservation. (we're working on the third).

I put my own uppers together!
D.R. #1741

Dave McGrath

1350 and 1259, we use White Oak Precision. :o) But I've put more than a few together myself.

Jeff

...My wife won't let me play with tools any longer.

If you end up taking the thing off, please let us know how large the gas port on the barrel is. Inquiring minds want to know.

B

Jerry,
How much would you sell me your barrel and bolt head for? I don't need anymore stray dogs or projects, but like Brian, Dave and Jeff, I do have an inquiring mind that needs to know.

I'll let you all know, gas port size etc., if it dosen't work next time to the range. I loaded up some more ammo with Varget and 4895, and loaded them in the mid range of the loading data. To note, that would have been to hot previously. I have returned the gas tube to 1.5 turns, and hope to be able to shoot it by sometime next week, I'll post the results. Thanks guys your'e all very helpful. Rost, as to that barrel, if DPMS won't do anything with it, I'll send it to you, OK?

Jerry

You are more patient than I am. Why don't you just put yourself out of your misery and send the damn thing to Jeff? (rhetorical question)

Whose tools is that?

Jerry

Yes I'd take the barrel. Chris F offered also, he and I are about like twins in trying to run things down to an end. Makes for a much better life when trouble shooting if you've done it a time or two!

If/When frustrated enough, just shout!

Jeff

Jerry;
Myself, I would gladly check out the problem. I have the tools and if it turns out there is a problem with the barrel itself, for whatever it's worth, I'll go to bat for you with DPMS. If I can fix your problem, I will charge you only for return shipping and "if" needed a part.
I'll also run various ammo through it too as a favor, at no cost.
I would not need the adjustable gas tube to solve the problem.
So there you have it, three guys willing to help or buy the barrel.
davear15yahoo.com

Dave McGrath

I'm telling your wife on you!

Carolyn will run/swim all the way over, and get on a bike and whoop up on ya...... think an AR could survive the saltwater swim portion?

After I tell her what you're saying online, I'll think she'll be whooping up on your sorry Butt!

You started it!

Jerry;
Did you get the problem solved? My offer still stands.

Dave McGrath

Jerry;
Don't know if your still having problems or not but I
had one of my DPMS barrels out to the range today for some chronographing and grouping before I begin my winter loading of about 4000 rounds.
The bullet that had the most powder behind it was the Sierra 60 grain HP. My favorite bullet for 200 yd. shooting. The charges tested were as high as 26.3 grains of Reloader 15. Thats a case full of medium burning rate powder without having excessive port pressure. More powder and slower burning rate equals more port pressure. As I reported before, no signs of chamber pressure, no cartridge rim damage in fact no problems at all with groups of one inch and a couple of others, even a little less. Range was 100 yards with no wind.
LC-90 brass, Remington 7 1/2 BR primer.
I also tested loads with Varget. No problems there either. Groups were the same but RE15 had the lowest s.d. of the two powders and higher velocity.
My gas port diameter is .0995". Bolt and carrier of unknown origin bought from Sherluk Marketing back in the late 90's.

Then to complete my day at the range on a happy note, no copper fouling in the bore! It don't get any better than that! $176.00 barrel at Midway USA product number 550-750!!!!!!!!!Dealers and C&R holders get them for even less!!!!!! I'm a happy man!!!!!

Dave McGrath

Hi Guys:

Sorry it has been so long since you all heard from me, but I haven't had a chance to shoot the AR since my last post. Holidays, hunting ETC. have kept me from the range. Today though 12/29, we got out to my buddy John's for some dove hunting, and an opportunity to shoot a couple 35 Whelens, in preparation for a buffalo hunt in Kansas next month, that also gave me a chance to shoot the AR, here's the results: No cronograph, as the sun wouldn't cooperate, clouds etc. I set the gas tube @1.5 turns as was recommended, fired a round with 25 grains of Varget/69 Sierra, and promptly tore the rim off. I then set the gas tube @1/2 turn fired the next Varget round, and the action didn't operate. So I opened up the gas tube to 3/4 turn, and fired the next round, which operated properly. I then went on to fire 22 more rounds with 4 different powder charges, and I had no more problems. 25 grains of Varget/69 Sierra put 5 in a group all touching, with one rim tear off a little outside of the group, and the one that didn't operate the action a little off that one. I then fired 25.5 grains of Varget/69 Sierra, not as good a group, I also fired a couple different loads with 748, but they were just miserable. Looks like you all may have been right about the gas port. I think the problem may be solved, but I won't know for sure until I shoot it again, and shoot some hot loads thru it for testing. I'll let you all know.

Happy New Year

Jerry

Jerry

Now if the gas tube solves it somewhat, then its time for a brand new extractor, as you've probably sorta wrecked that one a bit now ripping enough rims off.
It may still be a bad chamber though.... gas tube solved some issues, but not all. Would be nice to know how fast bare 69s with 25.0(a real standard load) are running though..

Jeff

Jeff: I will run some 69's/25 Varget over the crono in a week or 2 and let you know the results. I fired another 22 rounds thru it on New Years, and didn't have a problem.. My only angst here, I had to buy an aditional piece of equipment, in order to make this barrel work. It does look like it wll be accurate, more testing will tell.

Jerry

Jerry

Don't feel too bad, I"ve had Pac Nor barrels that don't shoot 90s that I use well at all, though they'll shoot everything else.... sometimes a gas tube is a cheap investment.....
Not that it should be like that, but each barrel is a beast unto itself. Nope PN would not replace my tubes and I don't expect them too, not when it shoots everything else in knots. It just goes on our NTIT guns...

Jeff

Jerry,
September 2007 American
Rifleman magazine has an article on the 223 chamber vs the 5.56 Nato chamber. You might want to look this one over real close.
whelennut