Hey guys.......

A friend of mine dropped off an older DPMS 22RF upper to me, to see if we could get the ceiner style of bolt to work in the thing.

This could be a big deal as DPMS no longer supports or carries parts for that particular upper anymore.

The barrel sticks into the receiver the same amount as any current set up does. The 2 glaring issues are the position of the extractor cut and that dia of the back end of the barrel (much less than .50")

Now......being TACCOM, I use our bolt, but.......you can use a CMMG, Spikes, Velocity, Ciener, etc.

I took the barrel out.....and with a dremel and a diamond wheel.....cut the extractor groove down to mate up with the extractor in the bolt. I didn't worry about the slop in the barrel collar to the barrel and figured that the collar centers in the upper and a little float is not bad.

Once I had the extractor groove modified, I re-assemble the upper, instal the bolt assy and attached to a lower for test fire.

The upper ran flawless.....ran a 50 round drum with no issues at all.

Soooooo.....if you have one of the old DPMS 22RF uppers (not current production), or know of someone that does.......ther eis still hope to get ting that thing running again.

OHHH......I should mention, the old magazines with the ejector built in will not work anymore and you need to run the Black Dog or CMMG style of mags.......but thats a good thing!!

Regards'
Tim

Several of us did this mod years ago before there were as many options available.  The biggest problem on my DPMS Gen I upper was the 10 round mags without a bolt catch.  The repeated hits from the firing pin on an empty chamber eventually Peened the end of the barrel.  This causes out of battery ignition which normally destroys the ejection port side extractor.  The bolt hold open followers all but eliminate this problem.  The Ciener pattern bolt is more robust than the Colt/ DPMS Gen I pattern bolt.  The two DPMS Gen I barrels I own are accurate and worth using and a tad more reliable with the Ciener pattern bolt.