CMMG dedicated .22LR upper

ChattanoogaPhil · Jun 24, 2016

I've had a CMMG .22 upper new in box for a about a year. Got it for a price I couldn't resist but never used it. With all the fuss about gun control lately I figured it was a good excuse to try one of those Palmetto State Armory complete lower "blems" that folks keep saying they like so much. So I clicked the buy button.

For starters, if there's a blemish on the PSA lower I have yet to find it. The fit and finish is every bit as good as others I own. It's tight on the CMMG upper and the hardcoat snodizing MIL-A-8625F, Type III, Class 2 finish appears to match perfectly with the CMMG.

The CMMG MK4T has a 1/16 twist M4 profile barrel with 1/2 x 28 threads. Props to CMMG for making the length of threads .4in for rimfire instead of standard AR length .6in. This allows rimfire suppressors to be mounted properly absent spacers that are commonly required on other .22LR AR platforms like my S&W 15-22 and Sig 522. It has an 11in Keymod handguard that I'll be finding a widget or two for mounting. The front and rear Magpul folding sights in the pic are not included.

The action is an interesting two part design that the barrel extends into about an inch. The finish makes it extremely easy to clean. The action is loud when shooting suppressed.

Took it to the range yesterday. I always use Minimags with a new autoloading rimfire. Flawlessly cycled a 100rd box. Then I tried a 50rd box of CCI Standard Velocity suppressed that also cycled flawlessly. Nice.

The standard GI trigger in the PSA lower I'll end up replacing but other than that I find nothing to gripe about and a lot that I like with both the CMMG and PSA.

CMMG MK4T
PSA complete blem Lower Classic Edition
Silencerco Sparrow
MBUS
Burris PEPR / Bushnell 1-4x
Black Dog magazine (CMMG does not include a magazine)

da gimp · Jun 25, 2016

CMMG is just down the road from us ( about 60 miles) They have an exc reputation for standing behind their goods & what few things that needed a tweaking had a fairly quick turn around too, even at the height of the AR15 sales madness several years ago. They also manufacture & sell Class III stuff... which is probably why the threading on their barrel is the proper length for mounting a suppressor....

Brian in Oregon · Jun 26, 2016

I've had a CMMG upper for a few years. Back then they called this particular version the Sierra upper. It has another name now. The lower is a Del-Ton. The hammer had to be changed from notched to rounded to properly function. The forend was the oversize M4 style. Swapped it out for the original CAR style.

Here she is all tarted up in Magpul goodness. The optic is an EOTech 552. It's been very reliable and shoots most subsonics well provided they are close to 1000 fps. The CCI Quiet 22 at 710 fps won't cycle most semi-autos. There is a little bolt clack but it pretty quiet. The mag is the original CMMG. I have some Black Dog mags and they work much better.

This is a nice conversion upper because it requires no changes to the lower except that it needs a rounded hammer. CMMG makes these in various styles from carbine to rifle.

I've done some side by side shooting with a S&W MP15-22, and both are a tie for reliability. The CMMG holds the edge for accuracy. There was no sound difference between the two with subsonics and a suppressor.

A10 · Jun 26, 2016

Nice looking rig Phil. I like the keymod system, mostly because I hate rails hanging up on everything. With the keymod you only have rails where you need them. Makes for a lighter rifle, too.

CMMG dedicated .22LR upper

ChattanoogaPhil

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da gimp

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Brian in Oregon

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A10

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