My experience with AR15 22LR conversions and dedicated uppers.

Thought I might share my experience with 22LR AR15's as there are lots of AR owners here and someone might be interested in building a 22LR upper or using a conversion.

I started down the 22LR AR15 rabbit hold when my wife bought me a CMMG stainless 22LR conversion bolt for my birthday. It worked OK in my 16" AR15 but with a 1:8 barrel it wasn't very accurate as the twist rate is way wrong for a 22LR. The 22LR was also really dirty in my AR and clogged gas ports can become a problem with prolonged used from what I've read. The CMMG also had a tendency to FTE quite a bit. 1-2 times per 27 round magazine. A 22LR round perfectly fits into the little channel on the underside of the charging handle. When you get a FTE it is often accompanied by some cursing as the round gets hung in the charging handle and you have to field strip the weapon to get it out. Bolt also tends to rattle around in the upper. All in all the initial experience just using the drop in bolt with an AR15 wasn't very positive.

Problem #1 with the CMMG kit: The extractor was for shite and didn't positively hold the round against the bolt face. Contacted CMMG and they shipped me a new extractor. New extractor didn't look much different than the old one and didn't fix the problem.



So I decided to use my 22LR conversion bolt and build a dedicated 22Lr upper around it. CMMG and Taccom3G sells dedicated 22LR barrels and they will come with a barrel collar which you remove the 223 adapter portion of the bolt assembly and the collar is the interface between the 22LR barrel and the bolt. The barrel collar has to match the barrel. The CMMG barrel collar is different than the Taccom3G barrel collar, but they both work with the same bolts. So you can't take a bolt with a CMMG barrel collar and take it out of your rifle and put it in an upper with a Taccom barrel. The most popular bolts will follow the Cienner/CMMG pattern and will have parts interchangeability.





Built upper using a 6.5" CMMG barrel. Built pistol lower. Bought a CMMG 22LR charging handle that doesn't have the channel in it so 22 shells won't get jammed in the charging handle. As an FYI the CMMG charging handle is polymer, some people don't like that. You can also take a regular charging handle and fill in the channel with JB weld to keep rounds from getting jammed in it. Went to range and shot. FTE problem even worse. 2-3 times per 27 round magazine with some Winchester Super-X 40gr. Bulk pack ammo even worse. My thought is with the shorter barrel

Taccom3G makes a lot of 22LR parts. Barrels, collars, bolts that follow the Cienner/CMMG pattern, parts for the bolts, etc. Many of their parts are to make the Cienner/CMMG pattern bolts more reliable. They also sell their own bolt and if I had to do it over again I wold get it instead. I've never read a bad thing about their products. They are well build and well engineered and just work. Two things I would recommend getting. They sell what they call the extreme extractor. Bought the new extractor and all my FTE problems went away. Item #2 is the pressure plug.

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The pressure plug is that yellow thing in the bottom left of the picture. You shove it right on top of the buffer in the buffer tube. The face that mates with the bolt is "humped" so it sticks out just far enough past the buffer retaining pin that it makes contact with the back face of the bolt. This applies a small constant pressure on the bolt which keeps it from rattling around and also keeps the barrel collar from backing away from the barrel. Works great.

Now I can reliably ring a 5" steel plate at 50 and 100 yards with ease with my unmagnified optic. Works through a magazine with no FTE problems.