cmmg conversion

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mkrueger

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I ordered a CMMG 22 lr conversion kit last week from joebobs. Since then, ive tried 4 different kinds of ammo ( federal, remington bulk packs, etc), two different brands of mags, and tried all these combinations in three different ARs. It jams at least 3 times a mag, and normally 10-15 times a mag, out of all three rifles. Its basically unshootable, I spend more time clearing jams than i do shooting. Anyone have ideas?
 
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I can't help with the .22 problem but can say they have the best customer service i have worked with in a very long time on another matter.

You can find some info on the cmmg .22 conversion from others who have them over on ar15.com blue
 
Originally Posted By: mkruegerI ordered a CMMG 22 lr conversion kit last week from joebobs. Since then, ive tried 4 different kinds of ammo ( federal, remington bulk packs, etc), two different brands of mags, and tried all these combinations in three different ARs. It jams at least 3 times a mag, and normally 10-15 times a mag, out of all three rifles. Its basically unshootable, I spend more time clearing jams than i do shooting. Anyone have ideas?

I'd suggest contacting CMMG here to troubleshoot:

CMMG Contact Information

That definitely doesn't sound right. How many mags do you have and which ones are they?

Also, check to make sure there isn't a small rubbing mark on the bottom of your 22LR bolt carrier. SOMETIMES with a 22LR conversion kit or upper, a slightly out of spec bolt catch can cause the bolt to drag on it and slows down the action, causing a host of issues. The bolt catch can be slightly too tall and may need a bit of filing to bring it down a few thousandths.

Also, how much lube are you putting on it? It may need to be run fairly wet to function well until it gets fully broken in.
 
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What type of federal ammo did you try? I tried a several brands & types of ammo, including a few different federal, and the one that seems to really run well is the Federal 36 grain copper plated hollow points sold in the red 550 value pack at Wal-Marts....give them a try if you haven't....I also used a dry lube on the bolt rails and it seems these things take a couple hundred rounds to really start running right & dumping full mags w/o jams.
 


I have two mags.... the one that came with the kit and a 30 round pro mag. The promag works a little better than the factory mag, but there isnt that much difference. Ill check to see if the carrier is dragging, but it would have to be the carrier thats would be out of whack somehow, unless all three of the ARs ive tried it in have an out of spec bolt catch.
Ive run it greased, that didnt work. Ive run it sopping wet with rem oil and ive run it totally dry without any lube, just to rule that out. It worked the same every time. Ill give CMMG a shout and see if they have an idea.
 
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Originally Posted By: tactical assaultI had the same issues with mine. My chamber was rough so I polished it and it solved the issue.





How did you polish it? Steel wool or something?
 
Originally Posted By: roof_monkeyWhat type of federal ammo did you try? I tried a several brands & types of ammo, including a few different federal, and the one that seems to really run well is the Federal 36 grain copper plated hollow points sold in the red 550 value pack at Wal-Marts....give them a try if you haven't....I also used a dry lube on the bolt rails and it seems these things take a couple hundred rounds to really start running right & dumping full mags w/o jams.

Ive tried federal 36 grain copper plated hps, but i got them from scheels and they were in a blue 525 rd value pack. I also tried federal auto rifle ammo, remington golden bullets, and one other one i cant think of off the top of my head.

I probably have close to 200 rounds thru it...
But it took awhile!
 
Originally Posted By: mkrueger

I have two mags.... the one that came with the kit and a 30 round pro mag. The promag works a little better than the factory mag, but there isnt that much difference. Ill check to see if the carrier is dragging, but it would have to be the carrier thats would be out of whack somehow, unless all three of the ARs ive tried it in have an out of spec bolt catch.
Ive run it greased, that didnt work. Ive run it sopping wet with rem oil and ive run it totally dry without any lube, just to rule that out. It worked the same every time. Ill give CMMG a shout and see if they have an idea.

If you tried it on multiple lowers then it could possibly rule it out, but not entirely as many manufacturers use the same part sources, although it would be rare. The blowback 22 uppers just don't have much force backwards so any interruption in that action could cause major issues.

I've never heard much about the Promag magazines, but BlackDog is really the industry leader on the 22LR AR mags. CMMG's makes should be GTG as well.

With that many different lubes used as well, I would think there is something else being the culprit. You've ruled out most of the possible issues with other equipment (mags, lube, lowers). Definitely give CMMG a call.
 
I called CMMG this morning. The guy on the phone asked if I had a black or stainless model. when I said black, he said "thats probably the problem". He gave me the option to send it back and they would try to get it running, or I could upgrade to the stainless version for 30 bucks. He recommended the stainless one. I opted just to upgrade to try to avoid problems in the future.
Customer service was pretty good, I was only on hold for probably 30 seconds, but its still going to cost me to ship the old one to them, and now have to fork out another 30 just so I can get a product that works the way it was supposed to in the first place.
 
Originally Posted By: mkruegerOriginally Posted By: tactical assaultI had the same issues with mine. My chamber was rough so I polished it and it solved the issue.





How did you polish it? Steel wool or something?

I little rubbing compound on a brass bore brush. Chuck it in a drill and run it back and forth until it is shiny. It does not take much.
 
Originally Posted By: mkruegerI called CMMG this morning. The guy on the phone asked if I had a black or stainless model. when I said black, he said "thats probably the problem". He gave me the option to send it back and they would try to get it running, or I could upgrade to the stainless version for 30 bucks. He recommended the stainless one. I opted just to upgrade to try to avoid problems in the future.
Customer service was pretty good, I was only on hold for probably 30 seconds, but its still going to cost me to ship the old one to them, and now have to fork out another 30 just so I can get a product that works the way it was supposed to in the first place.

That kind of surprises me, because we sell a lot of the phosphate finished ones and have never had any issues. Heck, I have a circa 2008 phosphate CMMG conversion kit I bought personally that runs like a champ.
 


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