[miker84]

Finally put my CMMG 22 upper on the plum crazy lower. Snapped right on there. Changed the hammer to a blowback hammer to run the 22 per Joseph's recommendation. I plan to put some sort of red dot on it and some buis soon. I couldn't wait for optics so I cleaned everything up and took her out to the pond and fired off a mag full of Winchester 36gr hollowpoints with zero problems.

I realize that I could of gotten one of those conversion kits to fire through another AR or changed the barrel in another AR, but I wanted to leave my others alone and get the 1-16 twist rate. I can always slap another upper on this lower if need be.

•16" WASP Melonite Coated CM Steel Barrel
•1 in 16" Twist
•Mil-Spec 1/2x28 Threaded Muzzle
•Piccatinny Railed, Low Profile Front Sight Base
•Live Round Extraction
•Firing Pin retained by standard AR15/M16 Cotter pin
•Mil-Spec M4 Receiver with Ceramic Finish
•A1 Flash Hider
•Gas Deflector

Crappy cell phone pic:

 

[captain-03]

Great to see you have already put it to good use ... have not made my mind up on what mine is going to grow up to be!!

 

[JMS39339]

Looks good! :thumbup:

 

[Xd357]

Nice!

 

[crazyace85]

Mike I got a question for ya. I have a conversion kit that I can't get to fire half the time. I get light hits it seems. Would a blowback hammer solve my problem and if so where can I find one.

 

[miker84]

Mike I got a question for ya. I have a conversion kit that I can't get to fire half the time. I get light hits it seems. Would a blowback hammer solve my problem and if so where can I find one.

I believe the blowback hammer better aligns with the 22 bolt since the stock hammer is a little wide.

As far as the light primer strikes go, (not that I'm an expert)...
I know that many of the conversions can be picky about ammo. In general, I've heard that copper-plated ammo runs best. Also, the bolt assy can get very dirty as well as the chamber so be sure you clean the heck out of those areas. The firing pin itself can get gunked up and not function reliably.

What kit do you have?

 

[crazyace85]

Sarck I think is how it's spelled from tacticalinc.com

 

[miker84]

Sarck I think is how it's spelled from tacticalinc.com

Haven't heard anything specifically about those kits. Is your hammer notched or rounded and are your sure the hammer springs are installed correctly?

 

[VegasSMG]

Finally put my CMMG 22 upper on the plum crazy lower. Snapped right on there. Changed the hammer to a blowback hammer to run the 22 per Joseph's recommendation...

I'm not certain what you mean by a "blow back" hammer, but the stock P.C. composite hammer is .391" wide, while a standard mil-spec hammer is about .300" wide. As such, it would not fall into the channel of the .22lr bolt carrier for most .22 conversions.

 

[miker84]

Finally put my CMMG 22 upper on the plum crazy lower. Snapped right on there. Changed the hammer to a blowback hammer to run the 22 per Joseph's recommendation...

I'm not certain what you mean by a "blow back" hammer, but the stock P.C. composite hammer is .391" wide, while a standard mil-spec hammer is about .300" wide. As such, it would not fall into the channel of the .22lr bolt carrier for most .22 conversions.

You are correct sir.

 

[miker84]

A little update. I got out to the range yesterday with my Plum Crazy/cmmg 22. The rain/snow shut me down after about 1 1/2 hours. I shot over 300 rounds through it to break it in and site in my red dot.

As far as the lower, it functioned flawlessly....just about the cleanest break I've felt on an AR trigger.

I did have quite a few malfunctions which I attribute to the upper needing a break-in. The malfunctions decreased as the round count went higher, which seems to be the norm.

The Winchester 333 Plated 36gr HP had the fewest malfunctions, but the widest group. The Winchester HV 22 36gr Lead HP had the most malfunctions, but had the tightest group.

With my eyes and a red dot, 25 yds was about the max for putting them in a 1" circle. At 50 yds, a 3" circle was the best I could manage. I was just resting the mag on the table....not using a rest or vise.

I'm going to have to invest in a 22 mag loader and more mags and fill them up at home. This thing is fun to shoot, but I wore out my thumbs loading the magazines.

 

[captain-03]

You have about convenienced me to go the 22LR route with my Lower .... keep up posted on the progress ...

 

[miker84]

You have about convenienced me to go the 22LR route with my Lower .... keep up posted on the progress ...

Before anyone piles on, I know that I could have gone out and bought a 10/22 for less than what I've got in this thing. I also could have gotten one of those conversion kits for my other AR's. But this is more fun :evilgun:

I shot a regular AR with a 22 conversion kit in it before going this route. It would light up all 8" of an 8" square at 25 yds all day long. That's still pretty good for plinking and a ton of fun. But, it just wouldn't consistently group....because of the twist rate I assume. Once I get this thing broken in and fully sighted in, I wouldn't be afraid to use it for critters. When I bush-hog my place in the summer, there are big fat field rats jumping everywhere for a couple of days. I'll have a surprise for them this summer!

 

[judgedelta]

where did you get the cmmg .22 upper, mags., blowback hammer, etc? thanks...

 

[miker84]

The hammer comes from Plum Crazy. You have to request it when you order...or get it from the nice guy who's selling the Plum Crazy lowers.

I caught the upper on sale at Midway several months ago along with the Black Dog Mags.

 

[judgedelta]

Thanks. I got a new Midway catalog today. I'll PM Joseph about the hammer...

 

[SubGunFan]

What is different about the blowback hammers?

Do you still use the original hammer spring?

Oh yes, the 1:16 twist should be much more accurate than a 223's 1:9 twist.

.

 

[miker84]

What is different about the blowback hammers?

Do you still use the original hammer spring?

Oh yes, the 1:16 twist should be much more accurate than a 223's 1:9 twist.

.

The stock plum hammer is too wide to fit between the rails on the 22 bolt assy. I used the same hammer spring. No light strikes so far.

 

[SubGunFan]

Yes, my PlumCrazy hammer is too wide for my 9mm upper. But a milspec hammer will work. I also have a Target Master 22RF conversion kit that I use in my AR-15 "Shorty" (11.5" barrel w/ 5.5" flash suppressor) with good results as function goes (maybe not accuracy). The Shorty has a milspec hammer and spring.

The reason I ask about a blowback hammer is I plan to replace the Calvary Arms lower on my AR-15/9mm with the PlumCrazy lower. An AR-15/9mm is blowback, not gas operated. I have heard that AR-15/9mms are hard on the hammer (mainly running full-auto).

Just wanting to know what is "special" about an AR-15 blowback hammer......

.

 

[miker84]

Yep, a regular milspec hammer would work in there. Not sure how the other parts would wear with a metal hammer though.

That's good to know about the 9mm. A pistol-caliber AR is on my list of stuff to build.