CMMG stainless .22 conversion range report


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halfded
January 4, 2010, 05:21 PM
On Christmas Eve, after much hemming and hawing, I placed an order with CDNN for a CMMG stainless steel ar15 .22lr conversion kit. The deciding factor was the special they were running:

-The stainless conversion kit with handy-dandy storage tube and 2 25 or so (can't remember exactly, that's all I'll be putting in them) round magazines. They even threw in a Colt screwdriver keychain.

Price before shipping: $189!

Due to the Holidays, it didn't arrive until today. It sat in a warehouse about 30 minutes from my house because they closed early for the holidays and I was too late calling to pick it up. :banghead:

The kit arrived in 2 heavy plastic ziplock bags, handy for later parts storage. The conversion bolt itself comes in a plastic tube with rubber endcaps; a lot like the ones at Lowe's or Home Depot to store screws and hardware bits in.

Quality of the bolt looks good. All the welds are as they should be and the conversion runs smoothly when cycled by hand. If I cycled it really slow I could make the extractor hold the bolt open, but I practically had to set the bolt onto the breech face to get it to happen.

The mags feel like, well, mags. They're metal and have some heft to them. I haven't loaded them fully yet, but I imagine they'll be very similar in loaded weight to a real mag. The followers run smoothly up and down and look almost like humpbacked GI followers. The followers are polymer of some sort instead of metal. We'll see how they hold up in the long run.

I'll be running the kit in a Spike's Tactical lower with Del-ton everything else, until my Bill Springfield FCG shows up. 16" standard barrel, A2 setup, no free float tube.

Before installing the new bolt, I coated everything in FP-10, especially the mock .223 casing that serves as the .22lr chamber. Yanked out my bolt and put it in the nifty storage tube. I lined up the conversion bolt and slid it into my receiver.

The first thing I noticed right off is there isn't enough spring tension on the bolt to lock the charging handle unless it's released from full battery. My charging handle is still fairly new; either way, no big deal. Went to close my lower and it looked like the bolt was hanging out too far. Gave it another firm push after another thin coat of lube and it slid in enough to allow the rifle to close. The back of the conversion sits RIGHT up against the buffer tube, though it's not used. I assume this helps to stabilize the bolt assembly.

I cycled the action and did a function check. Everything works normal, except for the bolt release; which is rendered inoperable by the conversion assembly. Again no big deal, the magazines have a last shot hold open feature.

I loaded 5 rounds to function check it. I shoot Federal Lightning, now called Champion, in all my .22's. It's cheap and clean; if a gun won't shoot them, it's gone. It's too cold here to do any prolonged shooting, but I walked out back, chambered a round, and all 5 rounds fired and ejected as they should. The brass even kinda flies the same direction!

THIS THING IS COOL!!!

I went back inside and loaded up another 10 rounds and grabbed a target. Hung up a 4" bullseye and fired 10 rounds offhand at 25 yards. Using my standard sight setting (zeroed at 50 yards), the rounds were hitting about 6-7 inches low, which at 50 yards would probably be (I'm guessing) 4-5 inches. Since I only hit the bottom edge of the paper and got a lot of mud splatter, group size was inconclusive. I also might have gotten a little trigger happy toward the end; did I mention this thing is fun?

Took my rifle back inside and cracked 'er back open. It took a minimal amount of effort to get the conversion back out (I think I need to clean my chamber a little better). Those of you that have a 10/22 will know what the inside of the receiver looked like. Thin gray film of residue from the barrel to about an inch past the edge of the gas tube. I'm curious to see how nasty it gets when I really have time to go shoot it. The barrel was about on par with any other .22 barrel that had just shot 15 rounds.

I'm really excited to get out and run this thing through it's paces. It's gonna be great to finally be able to enjoy shooting my rifle more often without chasing brass and spending a fortune. Unless something goes awry with it, this will probably be considered the best purchase of 2009 for me.

GO BUY ONE!!

Pics to follow...

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halfded
January 4, 2010, 05:46 PM
http://i625.photobucket.com/albums/tt332/halfdedsphoto/001-1.jpg

http://i625.photobucket.com/albums/tt332/halfdedsphoto/002-1.jpg

halfded
January 4, 2010, 05:48 PM
http://i625.photobucket.com/albums/tt332/halfdedsphoto/003-1.jpg
Sorry, I forgot to put cocoa butter on my awesome thumb muscle before I flexed out during the pic.

halfded
January 4, 2010, 05:50 PM
http://i625.photobucket.com/albums/tt332/halfdedsphoto/004-1.jpg

Sure wish my BCG was stainless..:(

halfded
January 4, 2010, 05:51 PM
http://i625.photobucket.com/albums/tt332/halfdedsphoto/005-1.jpg

And after

http://i625.photobucket.com/albums/tt332/halfdedsphoto/006-1.jpg

halfded
January 4, 2010, 05:52 PM
Note the hold open on the follower. My only gripe is I wish they had made these in metal. See how they hold up though.

http://i625.photobucket.com/albums/tt332/halfdedsphoto/007-1.jpg

Update: Got time to run another 30 rounds through the conversion today. Still no malfunctions to speak of. I got my sights adjusted for 25 yard shooting. With a 50 yard zero (5.56) at 8/3 -2, small aperture, nose to the handle, and all that, I had to set my sights at 5 +2 to get on target. Posted below is said target. First 10 rounds were fired sitting at a picnic table using the mag as a monopod. The rest were fired offhand standing. Shoots good enough for me! That's a 4-inch bull by the way, don't mind all the little holes in the paper. Splash back from my Do-all bullet trap box. Another nifty little contraption for .22lr shooting. Mine's taken thousands and thousands of rounds and has been sitting in my yard for going on 4 years now, no serious rust problems or weakening of the steel.

http://i625.photobucket.com/albums/tt332/halfdedsphoto/001-2.jpg

CnRnut
January 4, 2010, 07:50 PM
Nice write up.
I need to pick myself up one,as my Bushy doesn't
get shot any more. I went with a dedicated upper on a DoubleStar
lower for my plinker,but the Bushy yells at me to shoot her.

distra
January 4, 2010, 07:59 PM
http://www.thehighroad.org/showthread.php?t=495490

Here is my quick write up on the parkerized version. It runs great in my Stag AR. Mags are tedious to load up to 25, but functioned great for me. Botach Tactical has Black Dog mags on sale. Too much fun, this has to be illegal! :D:D

halfded
January 4, 2010, 08:35 PM
Too much fun, this has to be illegal!

My thoughts exactly!

hadmanysons
January 5, 2010, 01:10 AM
Nice write up. I would like to get on myself.

halfded
January 5, 2010, 04:52 PM
Updated to add picture of target and sight settings. See post #6.

rogertc1
January 5, 2010, 06:15 PM
Nice write up~!!! I have a dedicated Blackthorne upper /AR myself. With 3 Blackdog 30rd mags it was $408 delivered. And it does work even with the polymer upper.

trigga
January 5, 2010, 11:58 PM
i have the spikes .22lr conversion and i wish i would've knew about it years ago. imagine all the .223 ammo price. cool now that cmmg has the stainless finish i might get that when i get my next ar15. spikes has a 1 year warranty and cmmg has lifetime if im correct. this kit along with my gsg5 is a blast at the range.

Bula
January 6, 2010, 09:57 AM
Great review, now I really need to get one. Thanks.

Dr. Tad Hussein Winslow
January 6, 2010, 10:00 AM
Very nice; thank you; looks like a quality piece. Wonder if the "full shroud" CMMG mags will work with my Atchisson-Ceiner kit..

halfded
January 6, 2010, 03:45 PM
Mind posting a pic of your mags for comparison purposes?

Wahoo95
January 6, 2010, 04:08 PM
Yes, CMMG mags work with the standard Atchisson-Ceiner kit since it's essentially the same thing. Once the patent expired companies like CMMG were able to reproduce teh design.

CnRnut.....depending on what type of dedicated upper/bolt you have you may only need to get a chamber adapter to use it in your Bushy(5.56). I have a Spikes dedicated ST-22, however I also run the bolt in my 5.56 LMT using the chamber adapter on occassion.

The CMMG mags are nothing more than a desgn VERY simliar to Black Dog Machines...both work well!

Gunman21
January 6, 2010, 10:09 PM
I have had extraction problems with my CMMG conversion. CMMG said it was due to a notched hammer? Do you guys have rounded hammers or notched hammers?

Gunman21
January 6, 2010, 10:11 PM
Here is the convo I had with CMMG. Some good troubleshooting info here if you are having problems.

ME:
Hello,

I recently purchased a .22 conversion for my AR15. It will not feed more than 2 rounds of ammo without having an extraction problem. The round will simply stay in the chamber. I have been using Federal Ammo as suggested by CMMG. I also used 3 other types of .22 ammo and have still had an extraction problem. I do not know how to fix the problem, I would like to not go through the hassle of return shipping but do not want to void the warranty by tinkering with the product. If this is not an easy fix, how do I replace the kit? Thank you.

CMMG:
What grain of ammunition are you using? The kits usually run best with 36
grain ammo or less, as the bullets are shorter.


Thank You,
Eric

ME:
They are 36 grain. I believe it is a problem with the extractor. Even after the jam, I am not able to extract the cartridge by racking the charging handle. I have to manually pull the cartridge out with my finger nail. I believe the extractor is not able to close over the rim of the cartridge completely.

CMMG:
The extractor is not designed to extract live rounds, it is designed to be
blow-back operated. How many rounds have been fired through the unit?

ME:
Ive been doing some more research. I see you recommend a 200 round break in. I have only fired about 100. Is this due to a stiff spring in the unit? I also discovered I have a notched hammer. Will the notched hammer cause an extraction problem or a firing problem? All rounds have been able to fire and only the empty casing is stuck in the chamber.

CMMG:
The notched hammer will cause those problems. The break-in period will
allow the finish to "polish" up and let operate smoother.

rhinoh
January 7, 2010, 03:49 AM
The mags feel like, well, mags. They're metal and have some heft to them.


Might look at those mags again. I have the same kit and mags are the same as your pictured ones, they aren't metal.
I've been very pleased with my kit...lots of fun for cheap compared to .223/5.56 ammo.

halfded
January 7, 2010, 07:04 AM
Oops! :o You're right! Didn't have them sitting in front of me when I was writing this and it somehow slipped my mind. Wishful thinking maybe?

Gunman21: I am using the mil-spec hammer which has a small notch about an 1/8" from the top edge of the hammer. Hasn't caused me any problems at all.

It's still cold as a well digger's ass here so I've been running a little ammo through at a time to get it broken in. Put another 50 through yesterday, 25 as fast as I could pull the trigger. The only problem I had was resisting the urge to go inside and get another box (brick!). I think the stainless kit really improves out of the box function; even the wife commented how smooth it runs and how it feels "just like the other one" (same gun but shooting 5.56).

I still wish they could have gotten the bolt release to work, but you can't have it all. I still give it a whack on reloads to keep a habit established.

Geneseo1911
January 7, 2010, 08:10 AM
Thanks for the RR halfded. I've been thinking about one of these conversions, but I was under the impression accuracy was very poor, and one could expect at least 1 jam/mag. You have shown otherwise. I would be interested to see what it could do off a rest or a slung prone position. I look forward to a springtime update!

bhk
January 7, 2010, 10:09 AM
How much do you guys have to change your sights when going from rimfire to centerfire at, say, 25 yards?

Wahoo95
January 7, 2010, 10:26 AM
My POI is the same at 25yds.

Everything you need to know about the accuracy of the .22lr Conversions compared to dedicated uppers.

http://www.ar15.com/forums/topic.html?b=3&f=15&t=441890

halfded
January 7, 2010, 05:16 PM
I think the stainless version makes a big difference in reliability from my research. Haven't really found anyone talking about problems with the stainless, unless it was hammer or ammo related. I'm really looking forward to the weather warming up so I can have a chance to (ab)use this thing properly. Especially since I got my Bill Springfield trigger in the mail today. The conversion works with the new FCG as well.

As far as changing sight settings, I have mine set at 50 yard zero for regular shooting; rear sight 8/3, small aperture. My 25 yard zero is 4 +2. I haven't gotten to shoot the conversion at 50 yards yet, but at 25 yards with 40gr federal ammo, I set my sights to 5. Add 3 clicks up to any of these for large aperture setting.

Once the temperature breaks freezing (hopefully Sunday), I'll break out the sand bags and see what she'll do. Even the group I pictured above is a lot more than I expected as far as accuracy goes.

BTW, I'm keeping a round count on both the conversion kit and the Del-ton upper I'm shooting it through. May provide some valuable bargain consumer info down the road.

Geneseo1911
January 7, 2010, 05:50 PM
another question; On the arfcom page linked to above, there is discussion of twist rate being critically important to conversion kit accuracy. What is the twist on the barrel you are using? Also, is it the standard M4 profile?

halfded
January 7, 2010, 08:03 PM
Not sure about the M4 profile; I just came down with the disease recently. My gun is a Spike's lower with a Del-ton 16" rifle kit to finish it off. 1:9 twist. Works just fine for me out to 25 yards with what I've seen so far. That's the distance the target I posted was fired at.

Dedicated .22lr barrels usually use a 1:16 twist, which is slower if I'm not mistaken than the 1:9. One rotation of the projectile for every X number of inches of barrel.

rhinoh
January 9, 2010, 03:52 AM
Here is the convo I had with CMMG. Some good troubleshooting info here if you are having problems.


ME:
They are 36 grain. I believe it is a problem with the extractor. Even after the jam, I am not able to extract the cartridge by racking the charging handle. I have to manually pull the cartridge out with my finger nail. I believe the extractor is not able to close over the rim of the cartridge completely.

CMMG:
The extractor is not designed to extract live rounds, it is designed to be
blow-back operated. How many rounds have been fired through the unit?




Hmmm....I had the same experience with the extractor not grabbing the rim but I "fixed" it-

http://www.thehighroad.org/showthread.php?t=478081

Maybe I should have left it alone, but it works great in any case and will extract live rounds now...:uhoh:

cyclopsshooter
January 9, 2010, 04:13 AM
will those cmmg mags work with the colt conversion?

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