I simply can't afford to shoot 5.56mm on a regular basis. In fact, I've sold off most of my AR stuff because it collects more dust then anything. For this reason I've decided a dedicated .22LR would be a good investment.

At first I thought I would just buy a pre-built .22LR AR. I checked out the COLT brand ones but they seem kind of crappy. I looked at the M&P 15-22's but they seem to be too proprietary for my tastes I decided to build my own upper.

First item I got (birthday gift) was a CMMG .22LR barrel and chamber adapter.

Now I guess my question is do these things build like real 5.56mm AR-15's? If they do I think I pretty much have everything else I need other then the .22LR conversion kit itself. Here is the list of parts I have laying around from another AR I parted out that I can use for the build:

Daniel Defense Mk18 RIS II Rail (includes its own barrel nut)
Knights SR25 front and rear flip sights
RRA M4 complete upper receiver

Now I won't need a gas block and the rail covers the area where it would go anyway so from a visible stand point, that is a non-issue. I guess all I need to finish the build is a CMMG or another brand of .22LR Conversion kit and some magazines.

Would make a sexy MK18 MOD1 build if all the parts work smoothly together. Are there any issues anyone can think of?

Sounds like a cool project to me.. I don't know of any pitfalls you might run in to..


Good Luck,
SpecOps-13

Basically, I want to build the gun seen below.

They build exactly like .223s, except you have to modify the insert of your Brownells action vise or the top fromt of youyr DPMS action block to accomodate the barrel , which sticks further into the receiver than .223.
You still have to index the barrel nut so the handguard isn't cocked.

You can duplicate ANY configuration.
I built a MK12 Mod0 SPR.

I use the clam shell type action block when I build. No mod is necessary. However, if you are going to use the .22 deflector that attaches to the dust cover, you will need to cut out a section for it.

I would strongly suggest getting the CMMG Evolution bolt. It will give you live round extraction, cotter pin holding the firing pin and push pin holding the extractor.
Mine have been absolutely reliable.
Dave

Good point.
If the dust cover is off, no mods of the clamshell are needed, but if the dust cover is on, the internal insert won't go all the way in AND  let the cover close AND let the clamshell close.

Well shit... I just realized I can buy the whole CMMG Evolution upper for only like $90 dollars more then what the barrel and the CMMG Evolution conversion will cost me.

I'm half tempted to just do that and sell the barrel I got.

I also drill a 1/2" hole in the end of the insert. Forgot that!

This is in the t-handle insert that fills the upper when you have it in a clamshell?

I get a Gunsmiths discount on parts that I buy. I can't build an upper for less than buying a CMMG.
I can't build a rifle as inexpensive as I can buy from CMMG. The idea of buying a complete setup
from them and then changing a barrel is a very smart thing to do...Or, you could just have CMMG
build the upper or rifle of your dreams. The possibilities are endless.....


Spec

Yes. Took about 20 seconds. I drilled it about 1". The .22 barrel fit's right in it.

Only reason I took mine apart was to change hand guards. But it is real hard to beat CMMG's pricing.
Dave