Hey guys.  I'm looking for a bit of help.

My friend has a new style DPMS dedicated .22 upper (purchased from Midway USA about a month ago).  It is the 16" Bull Barrel model.  He is having consistent Failures to Feed.  The rifle will extract and eject the spent round, then attempt to chamber the next round.  The "bullet" (Lead) part of the cartridge will chamber, but not the case.  Upon extraction, the bullet is bent.  

The upper has a little over 1000 rounds through it.  He followed the DPMS break in instructions.  He has tried the upper on 3 different lowers (all 3 lowers work will with other .22 uppers on them).  He is using the factory 10 round mag, as well as BDM 15 and 25 round mags.  The BDM mags are known good mags - they work in other rifles.  We have tried running the rifle with and without the buffer and spring in the stock.  We have tried different followers in the BDM mags (hold open, non-hold open and original Ciener followers).

Ammo tested is CCI Blazer 40 grain, Federal Champion (Lightning) 40 grain, Remington Thunderbolt 40 grain, Winchester Wildcat 40 grain, Federal Bulk Pack 36 grain, Winchester Super X 36 grain.  Of all types, the Federal Bulk Pack and Winchester Super X seem to work the best (about 90% will feed).  Federal Champion (Lightning) is about 75%, the rest are less than 50%.  When firing, you can see the bolt speed is much faster / snappier with the 36 grain loads (Federal Bulk Pack, Winchester Super X).  Brass is ejected further as well.

He has tried running the bolt wet and dry.  He has kept the upper and bolt assembly clean.  He has cleaned the chamber using a chamber brush, as well as a bore snake.  We can see / feel no rough spots / burrs on the feed ramp or chamber.  

Any ideas on what can be done to fix this?

Thanks for your help!

Brad

Contact Tim at Taccom about it.

Dave N

carefully examine the face of the bolt for any imperfection that may catch or snag the rim as it "rides" up the bolt into battery, and this also includes the firing pin. if the firing pin or firing pin spring is broken, the firing pin may protrude past the face of the bolt during the feed stroke and catch the rim, preventing the cartridge from fully chambering. another possibility is the extractor, make sure it has enough travel to allow a cartridge rim to ride past it. it may be a good idea to remove the extractor from its channel, and thoroughly clean the channel. if a piece of grit or bullet gets inside the channel it may cause problems. make sure there is nothing else in there that shouldn't be there. next, examine the edge of the extractor for microscopic burrs or gouges, remember that the rim is in contact with the edge of the extractor during the feedstroke.

Thank you!

Tim:  if you see this, I have sent you an IM.

Brad

Contact made with Tim - he gave me some ideas.  We are going to test the upper out this weekend.

Thanks!

Brad

Brad.....how did things work out?

Hey guys.

We did some testing this weekend with mixed results.  Before heading to the range my friend buzzed the chamber and polished the feed ramp.  We took out the extractor and cleaned it.  The upper was given a good cleaning.  We were running the bolt wet.

We are still having issues with Failure to Feed, but only when prone or off the bench.  When standing or sitting we are not having any problems.  I can't figure out why - if it is a coincidence, or if it has something to do with pressure on the rifle / how it is being held.  When prone or off the bench, we have used both a bipod and rifle rest.

We tested the upper with all of the same ammo from last weekend, plus some CCI Mini-Mag 40 grain rounds (these worked the best).  It seems that this upper likes copper washed .22's - the loads that work the best are Mini-Mags, Federal Bulk Pack and Winchester Super-X.  

My friend ordered a new extractor (Volquartsen).  It was delivered yesterday.  We'll put it in and try that this weekend.

If anybody has any other thoughts, please let me know.

Thank you!

Brad

Make sure you're not resting on the mag...

No sir - the mag is not making contact with the ground.

Just an FYI....the volquartsen extractor MIGHT give you all sorts of headaches

Did you try feeding it with out an extractor?

Tim

both of my DPMS uppers (identical to yours) function flawlessly with almost any ammo that my son and I put through them. the only exception is the new and improved remington golden bullets. i bought a bucket of them and the only comment I can make is that crap must be manufactured on a treadmill in mogadishu. anyway, the only clue I get from your last post is that your feed problems are spring related. Have you checked the firing pin spring? it measures 1.730 in length and the wire is .022" diameter.

Hey Tim.

We did try feeding without an extractor.  We are having the same jamming issues.  Note - this was not firing, just chambering rounds.

We measured the firing pin spring - dims are the same as posted above.

Any other thoughts?

well, I guess my theory on the firing pin spring is total crap. moving on, at rest the firing pin is about .020 back from the boltface. the bolt is very nicely machined, and the melonite treatment really adds to the smooth finish, so a rough boltface isn't likely the problem either. the only suggestion I can give is to remove the firing pin, hang onto the CH and slowly feed live rounds out of the magazine and determine what the round is hanging up on. when the round hangs up jiggle the cartridge with the tip of a pencil to try and figure out where the pressure point is. the lowest portion of the bolt(the part that strips the cartridge off the magazine) is quite sharp, but it isn't rough.
     I tried this with my rifle and mine feeds the round very slowly every time, but the bolt doesn't quite go into full battery.( lazy owner hasn't cleaned it yet)  holding onto the CH and slowly letting the bolt go into battery, the bolt pushes the cartridge up the feedramp until the rim clears the feedlips, and then the follower on the magazine pushes the middle of the cartridge up level and evenly in line with the chamber. about half the bullet has entered the chamber at the point where the rim clears the feedlips. so with half of the tip of the bullet entering the chamber, the cartridge is fully lined up to go into battery.

Greetings,

Sorry I have nothing to add that hasn't already been suggested. I think the problem must be somewhere in the bolt and associated parts. OP, is there anyone near you with the same upper? If so, try swapping out the bolt group and see what happens.

My general question is ANYONE making parts available for these? DPMS will NOT sell anything proprietary to the upper (entire bolt group parts, firing pin parts, etc.). I had contacted the firm that had done the original design (based on a follow up to my post here) and licensed it to DPMS about a year and half ago to get some spares. They responded once, but then dropped contact when I tried to follow up. As this was during the big panic, I figured they were jammed up and let it go. But, this newer thread has me concerned again about getting parts.

FYI, my problem was an incompatibility between the firing pin length (seemed to be some variance from several respondents that measured theirs) and the Geislee FCG I was using. I ended up swapping in an older RockRiver 2 stage so I could get the upper off the bench and do some shooting. So far so good after a quite a few thousand rounds. Anyway, if there is a good lead on parts sources, I'd appreciate an update. Thanks much!

Regards, Jim

Maybe Tim will chime in but I thought the 2nd generation DPMS/Nordic/JP bolts were essentially a Ruger 10/22 bolt design.  I have never seen a DPMS Gen II in person to examine the bolt.  If the bolt is that similar to 10/22 bolt are the parts interchangeable?

like the OP, I've come to the conclusion that the culprit is the extractor,  that seems the only real issue that is left. on the feedstroke the cartridge rim passes between the extractor hook and the boltface. it is possible that the bolt has been improperly machined for the extractor, and if it is improperly machined, the rim will catch the extractor on the way up and jam. on both of my uppers, the rim does not touch the extractor as it goes into battery, but the clearance is miniscule. I have also read that some of the Nordic/DPMS/JP bolts had problems with the extractor hole being improperly machined, and leaving only a few thousandths of material,and some bolts have cracked because of this. it isn't dangerous, but the extractor may not work properly.  check the bottom surface of the bolt for a tiny crack. if it is cracked, a new bolt should be fitted at the factory. if it isn't cracked, then fitting the new extractor is the cure.

I had a ton of problems with my CMMG dedicated upper.  The TACCOM stuff helped a little.
I got a Boonie Packer mag adapter and some S&W M&P15-22 mags and it ran flawlessly for 5 mags.  That's the only time I've shot it since, but I was AMAZED at how well it ran.  Was using Black Dog mags before.

Something to consider.  Plus the S&W mags arte nice to load since they have the little button you can use to compress the spring.  I'm SUPER happy.

Don't know what mags you run with the DPMS, but if it isn't S&W, try the Boonie Packer converter.

I have the identical DPMS upper that I got from Midway USA as well.

I shoot CCI .22 Tactical ammo in it almost exclusively. I have only had
one round fail to feed with that ammo. But that was shooting 250+
rounds without cleaning or lubricating. This fodder is copper plated and
has a blunt round nose. The bolt components are just lightly lubricated
with CLP.

I use both CMMG 26 (?) round and the factory BDM 10 round magazine
that came with the upper.

When shooting lead bullets I sometimes had FTFs as you describe. But
I only tried the lead ammo while initially testing for accuracy with the various
.22 LR ammo I had on hand. And the FTF rate was just one out of 25 or
50 as I recall. After my initial testing I have stayed with the CCI .22
Tactical ammunition. It functions great and will shoot to 1.5" @ 50 yards
using a 1x4x30mm scope. I run a military trigger in the lower.

If you can get some CCI .22 Tactical (or perhaps Winchester M22 or
NormaUSA TAC-22) ammunition that may solve the feeding problem.
They are supposedly designed for these types of rifles.

Good luck.

If I understand correctly, the hotter loads did better for the OP?

Hey guys.

Sorry it's been so long.  My friend called DPMS.  They told him they had not heard of any issues like this.  They advised that he either return the upper to Midway USA and get a new one sent to him, or send in the upper to them to look at.  DPMS said that if he sends the upper to them, it will take approximately 3 weeks to look at / fix and return.  

Thank you all for the help and suggestions.

Brad

That is correct - hotter worked better.  And for some reason, standing / sitting worked better than prone / off the bench / with a bipod.

I don't beleive the Boonie Packer and S & W mags will work with a DPMS upper.

Dave N