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Posted: 7/7/2005 8:38:33 AM EDT
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TOOK MY BRAND NEW NEVER FIRED DPMS UPPER WITH 16 INCH SS BULL BARREL AND CHROME BOLT CARRIER TO THE SUMMER HOUSE FOR THE HOLLIDAY. Fired a round (wolf .223 55gr hollow point)and the next round chambeed but would not fire. Could not pull the bolt carrier assembly forward or backwards. Had to remove the barrel from the upper to remove the round. Reassembled everything and the same thing happened again. Cleaned the entire setup. Switched out the carrier assembly with my bushy and loaded a round. Couldn't move the carrier assembly. Tried brass cased ammo with the same result. Swapped out the stainless barrel and put on a bushy superlight and the upper chambered round after round. It likely was the barell. Any thoughts. DPMS tried to blame the polymer coating for the jams. Can a single round of polymer coated ammo do this? P.S. DPMS is taking the entire upper back even though I bought the upper from midway and the carrier and barrel seperately from them. |
| The bull barrel is very likely, almost certainly, chambered for .223. The 5.56 ammo may or may not fire in a .223 chamber. That is very likely your problem. Compound that with DPMS having a notorious reputation for excessively tight chambers and, IMO, your result was not unexpected. |
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My DPMS 5.56 chamber digests wolf with no issues. Would I use Wolf with a .223 match chamber? Hell No! Why buy a match rifle and shoot cheap ammo through it. doesn't make any sense to me. I use Wolf ammo, but for plinking with 5.56 chambers. The 5.56 chamber has more "slop", allows for small variations that might be encountered. Use good match ammo and it should be fine. The polymer coating has nothing to do with anything. |
Was the more expensive ammo .223 match ammo like Black hills? That's what you need with a .223 chamber. Winchester .223 should also work. |
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For plinking, I would like to be able to run wolf through the barrel. .223 cases should fit in a .223 chamber, shouldn't they. Would one casing with a polymer coat cause a jam? The first case loads but wont eject. I don't know the manufacturer of the brass cased ammo as it was my cousins and he exchanged magazines with me to test out the problem. |
Your dealing with a tight match chamber. Alas no plinking with cheap ammo for you. your barrel was designed only for .223 ammo and good stuff at that. If you want something that will do both the wylde chamber would be a good compromise. IPSC_GUY SIERRA II ALPHA |
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The only difference between 5.56 Nato and .223 is the pressure that the round is loaded to. Both rounds should have the same dimensions. Now, It sounds to me that you have a chamber problem. Whether your rifle likes Wolf or not is irrelevant. You tried several types of rounds, it SHOULD have chambered them all. IMO, Send it back, make them fix what's wrong. |
It's the chamber that is different. The leade on a 5.56mm chamber is longer. A saami chamber is much tighter, resulting in better accuracy, but less tolerance in ammo spec and pressures. a good understanding of this can save you much frustration. |
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maybe with all this swapping of barrels you twisted/crushed the upper reciever causing the bolt carrier to bind against the upper. when hand cycling the first round the carrier has more force behind it and it closes all the way and with the weak wolf ammo there isnt enough force to drive it home. since you cant fire the second round but can the first mybe the bolt is not all the way home. when you take the barrel off does the round just fall out? |
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Nothing appeared crushed. I couldnt hand chamber more than one round after i cleaned the whole setup. The first round would load from the mag but i could not extract it from the chamber with the charge handle. I had to remove the barrel and the bullet would fly loose. |
Did the first case eject intact? Was any part of the case torn/ripped off staying inside the chamber? Check the chamber for any obstructions in the chamber. |
I'm not talking about the outside of the barrel. Remove the barrel from the upper receiver and shine a bright light into the chamber (not the barrel extension) to see if there's anything that's preventing a new round from being inserted/removed normally. If I drop a cartridge into my chamber (manually just dropping it relying 9.8 m/s^2) it will be rather tough to pull out manually unless it is extracted or pulled out. If you're saying once a new cartidge is chambered, it will be impossible to extract using the CH/bolt ? That suggests the chamber is somehow deformed or there is a foreign object in there. Check the headspacing while you're at it. |
When you say the inside of the barrel, are you talking about the bore (near the muzzle) or the chamber and everything? I'm just curious as to why you could fire the first cartridge and then not another cartridge. I'm wondering if a tiny ring of the steel case broke off and fire formed into the shoulder area of the chamber preventing the chambering of the next cartridge.  I know you said the case was intact, but sometimes you miss something at the range... unless you kept the case and brought it home with you.I've heard the DPMS chambers (.223?) can be very tight, along with the Wylde Chambers. That's why I like my 5.56 NATO chamber.  I'll gladly sacrifice that 1 MOA so I can feed any .223/5.56 cartridge.Good luck and keep us posted. I'm sure DPMS is going to blame the evil dirty Wolf ammo.  More please!ETA: After reading your first post over again, it sounds like something was gripping the case way too tightly (foreign object jammed in the chamber). Did the cases show any weird markings when you finally got them out of the chamber? That could give you a sign as to why they weren't chamberng properly. |
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All of the subsequent cases that I chambered and removed by taking the barrel off showed marking along the bullet head itself along the long axis of the head and similar markings along the length of the case. DPMS said its the polymer when I spoke to them on the phone prior to sending everything back. I did clean out the chamber well and then had the same problem with brass rounds. I may have them exchange the barrel for a HBAR 16inch (5.56 chamber!) with a muzzle brake if they can't do anything. |
I've shot over 2000+ polymer cased Wolf ammo in a 7.62x39 chrome lined barrel. It's not the polymer. The worst the polymer can do is make the chamber look a bit red.  Can you take some pics of the bullets that you extracted? |
Yes, the chamber is different, but the bullets are the same!! That's my point. You're rifle doesn't know if you slap a Radway Green SS109, or an American Eagle .223 in it. Both rounds "should" have the same outer demensions. If it will not chamber either of them, the something is wrong with the rifle. |
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Update. DPMS has my setup and they states that they will correct the size of the chamber. The customer sales associate says that he will even bring in some of his own wolf ammo to ensure that the chamber is large enough to accept the steel casing. I'll let you guys know as I find out for those interested. Thanks for all the help. |
So the chamber was incorrectly sized from the start? How did you fire the first Wolf cartridge? the steel casing would be the "same" size as standard .223 remington cases. If the chamber could not accept the steel cases, then it wasn't sized properly in the first place (improper headspacing?) Keep us posted! |
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This is the message i got from DPMS: we have gotten your upper reassembled, head spaced and have test fired it with both surplus and .223 ammo. We did not have any problems with extraction or feeding. I will be shipping this back to you today. If you have any questions or concerns please feel free to contact myself. They told me on the phone that the headspacing needed adjustment and the gas tube needed to be "lubed."? They said is rana nd fired whatever ammo they tried. Should have it back for the weekend. We'll see. I have 900 round of 55gr wolf hollow points to try. |
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The gas tube lubing isn't mandatory but I always put a drop of lubricant around the "mushroom". It looks like the headspacing was originally out of spec and they had to ream the chamber? This is definitely a QC issue and not a result of you using Wolf. I'm looking forward to hearing your after action report this weekend if you get a chance to shoot it. |
How do you adjust headspace on an AR15 other than machining the chamber, or changing out the barrel and/or bolt? There are NO adjustable parts. smells like 
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Remachining the chamber would be the only way I can see to adjust the headspacing. Check to see if its your barrel that they return. Something so mismatched like this should not have left a reputable dealer/vendor. I know Bushmaster checks the headspacing on their barrels (or so they claim...) |
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Got my package from DPMS today after fighting with UPS on Friday (thats another story). Reassembled it onto my RRA lower. Placed an aluminum mag with 10 rounds and was able to cycle manually through the 10 rounds of wolf .223. Haven't been able to get to the range as the damn package didn't come on Friday when the 2nd day air should of had it delivered. Was not able to manually load any rounds prior to sending the upper back to DPMS. Will update after firing off some rounds hopefully this weekend. |
I read it on the MD AR-15 site IIRC. It said if the chamber wasn't chrome-lined, you could use a reamer. If it was chrome-lined, you can adjust the headspace via the barrel extension. I have no personal experience with this, just conveying what I read. But I can't access the MD Ar-15 site from this PC to get the link. |
Here's the quote. It doesn't sound right or logical to me. That statement doesn't jive with the barrel manufacturing process, as I understand it. Once the barrel is chromed, there is very little recourse in adjusting the headspace. "Tweaking" a barrel extension sound like a very bad idea to me. I'm not even sure where I would start. |
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Update! Finally got to fire the fixed reassembled upper and it functioned flawlessly. Ran about 40 rounds of wolf .223 hollow points through it and not a single jam. Love the new Aimpoint Compl ML3 with 2MOA dot I purchased for it. Gotta hand it to DPMS. They quickly turned around my upper even though I bought the bolt and barrel at sepearate times and the stripped upper from Midway USA. Thanks for everyone's input! |
I think they're actually threaded and pinned. WIZZO BTW, good to hear that they fixed it right for you. |
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