I have a stripped mil-spec upper / lower combo - any resources to learn about parts (bcg, barrel, etc.) to make it work like a mil-spec AR but eat, shoot & cycle .22LR?

I have 2 CMMG conversion kits and they run great with CMMG and BDM MAGS.
Neither will run with Rem gold ammo.

Just read here and you'll learn, ask questions, we have some very experienced hands here.

I have 2 Tactical Solutions uppers that run everything! Remington golden, cci standard, Winchester bulk, federal bulk win/fed hyper velocity HP's,etc I use BDM & CmmG mags, 25/32/50rd's all function perfectly. Only issue I had was the older Tac sol M4 upper using the older 6yr old bolt design wouldn't work on my RRA varmint 3.5lb trigger, but that that's being fixed now. my sbx barrel ar has newer bolt design , no issues at all! Good luck with the build.

SBR or non SBR? I would look at CMMG and TACCOM either way.

Mine works great with the following:  standard upper small parts kit, CMMG Bravo bolt kit, TACCOM ULW 22 LR barrel, MI gen 2 free float handguard, standard LPK minus FCG, RRA 3.5 lb varminter 2 stage trigger, Better-Mag S&W mag adapter, S&W 25 or 10 round mags.  All functions are same as standard AR in this configuration, mine has eaten every type of ammo I've given it including CCI SV which is subsonic.  I bought a TACCOM reliability kit but haven't yet had to use it.

Here's what I would recommend for a 22lr AR build:

Standard HG=
-Taccom/CMMG barrel & extension
-A2 FH & crush washer
-FSB, HG cap, delta pack & barrel nut
-forward assist plug
-CMMG 22lr/9mm dust cover kit
-CMMG conversion kit/bolt/carrier
-standard CH
-handguards

FF rail=
-Taccom/CMMG barrel & extension
-A2 FH & crush washer
-forward assist plug
-CMMG 22lr/9mm dust cover kit
-CMMG conversion kit/bolt/carrier
-standard CH
-FF rail

I use a standard anderson upper, cmmg barrel/bolt kit, cmmg .22 charging handle (doesnt have the slot underneath), taccom pressure plug, s&w better mag adapter. Lower is stock standard ar15 with a CMC trigger.

I would not bother with a 22/9mm dust cover kit, youll have zero issues without one.

just ... wow. in less than 24 hours more & better info than amazon books + lgs combined! thx to all who responded. because of you gents I just gave $$ to arfcom. will digest all the replies then circle back

Both CMMG and Taccom have really good stuff. We run some Taccom parts on one upper, including a ULW barrel. And one with standard CMMG barrel. Both have Stainless CMMG bolts. I like the stainless Bolts over the coated ones. But that is just a personal preference,. I am sure the Taccom bolts run just as good.

Mags, we use SW 15-22 and the better mag adapter. Best Mags out there. I would not even mess with CMMG mags, or Blackdog ones. Have owned both and ended up selling them all in favor of the SW ones. The SW ones are just too good to consider anything else. I do really like the Blackdog 50 round drums though.

As far as barrels and such, either Taccom or CMMG will serve you fine, I really like the light weight of the ULW from Taccom. But both our uppers run flawless with either the standard CMMG or Taccom ULW barrel. Aside from the bolt and barrel. The rest is just personal preference what you like..

We run standard Aero precision upper receivers and standard aluminum charging handles in both. Some say they have trouble using standard charging handles and use the CMMG anti jam plastic handles. (I hate plastic charging handles)

We have never, ever had a round jam in the standard handles through many 1000s of rounds with the CMMG bolts...

Quick and easy route is to build a 5.56mm upper and just use an adapter kit.  You'll get better accuracy with a dedicated .22lr barrel though - proper bore size and twist rate.

Mine is a 11.5" SBR upper.  Slickside upper, KKF dedicated .22lr barrel, M261 kit.  Works great and I have it sighted in to match my 5.56mm upper at 25 yards.  Literally swap 'n go.

Not sure who else makes dedicated .22lr barrels since Kurt was killed.  At the time I built mine, your adapter choices were either M261 or Ciener, and I refused to do business with the prick.  Today, I'd go with a CMMG or other good quality adapter.

My dedicated .22 is made up of a ceiner bolt, CMMG collar, CMMG 4.5" barrel, CMMG 22 charging handle, Anderson lightweight upper, and Daniel Defense M4 7.0 rail. I could only get it to feed federal and CCI ammo until I got the better mag adapter. Now that I can use the S&W magazines, I haven't run into any ammo I can't shoot.

Great info. Thx!

Some of these builds have nice, short barrels - is this because you are free men in free states - or does the minimum barrel length requirement for a 5.56 not apply to .22LR?

$200 = short barrel

Is it a dedicated upper or is it still the drop-in?  I have a few M261 kits, one of which I want to turn into a dedicated upper, but Compass Lake is the only one I knew about that was doing that work.

"... like I'm an idiot, please ..."

I built a dedicated .22lr for my son. Here is a list of the parts:

* Stripped Lower Receiver:  Spike's Tactical Calico Jack  $115
* Trigger/lower parts kit:  ALG Defense ACT $90
* Bolt Catch: DPMS  $8.00
* Bolt Hold Open Adapter: CMMG  $20.00
* Stock:  Magpul CTR Mil-Spec O.D. Green   $68.00
* Pistol Grip: MOE+ O.D. Green $22.75
* Buffer Tube Assembly:  PSA Premium 6 position Mil-Spec $29.95 (pinned, NJ laws suck)
* Stripped Upper Receiver:  PSA blem  $39.95
* Barrel with collar:  CMMG .22lr dedicated M4 contour $180
* Bolt - stainless steel with forward assist: CMMG $145
* Charging Handle: Bravo Company Mod 4 medium $26.00
* Hand Guard: Leapers UTG Pro 9" $78
* Ejection Port Dust Cover: Leo Armory custom engraved $43.95  
* Forward Assist: DPMS $12.00
* Rail Covers:  Magpul XTM Enhanced $31.00
* Magazines: CMMG and Blackdog  
* Sights: Magpul  MBUS Pro $125.00 set

I know this is more info than you needed but I just copied and pasted the list from a build list I kept.  You can buy most of this stuff cheaper today than what I paid for it 18 months ago. (the height of the scare)

I am now building a dedicated upper for my AR and I went a little different route, especially for the barrel and the magazines. I plan on using my original lower for now.
I ordered (currently waiting) a Clint Beyer target barrel and I bought the Better Mag adapter and a few 10 round (NJ still sucks) S&W 15/22 magazines. I'm told this is the best way to go. I didn't know this when I built my son's rifle.

I am curious, I know a lot of guys use CMMG & Taccon along with Better Mag adapter S&W mags. Is this bc the "norm" is they don't feed well or different ammo well w/o it?? MY Tac Sol uppers have no issues with feeding any ammo with standard BDM and CMMG mags . Just seems like more expense buying extra mag adapters, charge handles etc just to make them run & feed well.

Personally run the better mag adapter with s&w mags because I like the mags better. As a matter of fact I absolutely disliked the cmmg mags that I have. not to mention at the time I had a 15-22 so I had a nice stock of mags. But for ease of use, s&w mags get my vote over cmmg mags

No such thing as too much GOOD info. Thx!

Free state, but still pay the feds $200.

Dedicated upper.  The barrel uses an unmodified M261 and chamber insert, but has proper bore size and twist for .22lr.

Thx for the info on $200 piece.

Another question: 22lr is very dirty? Any reason not to go piston?

.22 conversions are blowback only (with the exception of the Air Force conversion).  A dedicated upper doesn't even use the gas tube.

My son has about 1500 rounds through his rifle and I think I'll clean it before the next trip to the range.  They are no dirtier than any other gun in my opinion.
Here is a pic of it just for the hell of it.