New upper. problems. More info!!!! > Troubleshooting

Posted: 12/30/2004 7:00:29 PM EDT

I just received as a gift a new DPMS 20" upper. Today I decided to take it apart and clean and lube the upper and I noticed that the bolt was stiff inside of the carrier. When I perform the 45 degree test the bolt doesnt quite go into battery from gravity alone. I have not shot the upper yet. Is this something I should worry about or should I shoot it first and see if I have problems? Do these gas rings and carriers need to be broken it slightly? I don't think my last bolt/carrie combo was that tight. hanksKevin

Posted: 12/30/2004 7:16:59 PM EDT

[#1]

The rings have a sharp edge on them when there stamped, plus the chrome lining in the gas section of the carrier is a tad rough when new. Just remember to lube all the upper's bearing surfaces of the rifle when you break it in (this means you put a few drops of CLP in the gas section of the carrier as well).

Posted: 12/30/2004 7:40:31 PM EDT

[#2]

Thanks for the info!! I thought that might be the case but never hurts to check this great resource.
Thanks

Posted: 12/31/2004 12:44:05 AM EDT

[#3]

does the bolt slide easily in the carrier when the rings are removed?

Posted: 12/31/2004 6:29:27 AM EDT

[#4]

I haven't taken the rings off but it seems to be that the when putting the bolt into the carrier that the rings are what causes the friction.

Posted: 12/31/2004 8:49:03 AM EDT

[#5]

I thought that I had read tha new rings require a slight break-in period? Is that true with new rings? I have had other new rifes and the bolt was not as sticky in the carrier.

Posted: 1/1/2005 2:09:41 PM EDT

[#6]

OK, so I got this upper to the range today and it would fire the first round and then the bolt would close without stripping a new round. tried 3 different good mags and 3 different types of ammo.
No luck. Also would not hold open on last round. there was another guy there who let me try his bolt to test and the rifle ran fine with his bolt and carrier. We tried various combinations of his carrier and my bolt and the only way it would run was with his bolt and carrier. What the heck is up with this?? It's a DPMS silver looking (chromed?) bolt. the bolt does seem stiff in the carrier. Coudl this cause this problem??
Thanks

Posted: 1/1/2005 10:15:11 PM EDT

[#7]

If you would of told use it was a DPMS chrome bolt/carrier, then I wold have instructed you differently.
Let me know when you get your hands on a stone, and steel counter sink, and some fine lapping compound because you have a good 20 min of work to do.

Posted: 1/2/2005 9:43:16 AM EDT

[#8]

My fault. I mnetioned the DPMS upper but forgot to specify the bolt material. this doesn't sound like fun!! I bet that I have to remove material around the raised ring on the bolt??
All the items you listed i am familiar with but the steel countersink. Could you point me in the right direction for this? Since it's brand new maybe I should just send it back and request a non-chromed bolt carrier?

Posted: 1/2/2005 9:52:23 AM EDT

[#9]

Since I do own Chrome B/C's, all I can say is that they are easier to clean since you can see the fouling. The problem is that some manufactures add chroming to standard size parts. This build up the surfaces/burs, and is where the problem lies.

If you just have to have a shiny carrier/bolt, I can walk you threw making it run. But, if you just skip the work, send it back and have them ship you a standard parkerized unit (both B and C).

Posted: 1/2/2005 10:04:57 AM EDT

[#10]

Thanks for your help on this. i will talk to them and see if they will send me a standard b/c. If it gets to be a hassle with them I might just keep this one and try and get it to run. I will give you a shout here on the board if I decide to try and make the chrome b/c work. You would think that so many people have problems with these that they wouldn't produce them without better Q/C. thanks again for the help!!!

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[ARCHIVED THREAD] - New upper. problems. More info!!!!

[ARCHIVED THREAD] - New upper. problems. More info!!!!