Does anyone have any experience with these?  I really don’t see any reviews on the NM models.

https://www.rockriverarms.com/index.cfm?fuseaction=category.display&category_ID=1992

There have been a couple post from purchasers on rimfirecentral.com.   The bolt appears to be the same as used on Nordic Component dedicated 22 LR uppers.  I suspect these are Wilson air gauged barrels from Wilson Arms in Connecticut, not Wilson Combat in Arkansas.    With Compass Lake Engineering (CLE)  not offering their dedicated service rifle trainer RRA is about the only option.   Bore Buddy is selling a 20” rimfire upper but uses a different hand guard.   The 20” barrel can be purchased and you can use a CMMG Stainless bolt.  


If you want a fully functional bolt catch the Bore Buddy barrel and CMMG bolt is what I would assemble.   PSA has the CMMG bolts for $99.99 and the A-2 hand guard and free float tube can still be found.


RRA still sell the free float DCM pattern barrel sleeve and you can buy an A-2 Fixed sight tower that his held in place by four allen screws instead of having the front sight pinned.


https://www.rockriverarms.com/index.cfm?fuseaction=category.display&category_ID=1263


DEZ Tactical Arms sell the A-2 front sight held on with set screws.  I used one of these on a 22 LR AR-15 build about 15 years ago.  I used red Loctite and his has held all these years.

http://shop.deztacticalarms.com/products/dez-tactical-arms-dez-1034-gb-751778882946-dez-1034-gb-6422


Here is a link to the complete A-2 sight including the post, spring, detent.


http://shop.deztacticalarms.com/products/dez-tactical-arms-dez-1035-gb-751778882922-dez-1035-gb-6422

Bore Body Match Barrel

https://borebuddy.com/product/borebuddy-apogee-match/

Palmetto State Armory 22 LR CMMG Bolt with barrel collar.


https://palmettostatearmory.com/psa-22-lr-bolt-carrier-group-stainless-steel.html

I bought the older Nordic Upper and put my own RRA NM free float on it.  I had a pair of Armalite iirc set screw front sight towers.  I have a bit of a mismatch front sight height wise with a removable carry handle.  Iirc I had to buy an extra tall post.

I had loads of problems with the Nordic (their early type with the 10/22 style bolt).   A member really straightened me out with all the jams by tossing the OEM extractors in the garbage and getting volquartzen extractors.  Night and day difference.  

I would have bought a RRA NM .22 upper in a heart beat back then.

oops came back for a double tap slo mo

Could you use something like this and build it


https://www.righttobear.com/rtb-20-inch-22lr-barrel-bolt-group-rtb22lr20gp-rtb-22ba487/


Red

The 20” CMMG or RTB 22 LR barrels have been out of stock for a couple years.   I got an email notice the RTB 20” barrel was in stock about a month ago.  I immediately went to their sight and the barrel was still out of stock.   It has been a very long time since I saw a CMMG 20” 22 LR barrel for sale.  The only 20” rimfire 22 LR barrel currently is the Apogee barrel from Bore Buddy.   It is listed as 21” but that is so the barrel will have the same appearance and overall length of the centerfire AR-15 20” barrel.   A 22 LR barrel sits deeper in the AR-15 receiver than a centerfire barrel.



https://borebuddy.com/product/borebuddy-apogee-match/

Keystone is another source. I believe they use gm blanks but I believe they have krieger or I believe you can supply your own

https://keystoneaccuracy.com/ar22/