[Jack B]

I've posted this thread for those of you considering a 22lr Conversion Kit for your Sig 516. After a lot or research, I ended up purchasing a Stainless Steel CMMG 22lr Conversion kit. Since I live in Kalifornia, it was a major issue just finding 10 mags that would function properly. Here's what I ended up with, and it works flawlessly in my Sig 516. The CMMG is major quality, much better than the Colts and Ceiner Kit's I"ve used in other AR's. It can be found for about $175.00 on Gunbroker. Finding the 10 shot mags were almost impossible, CMMG was out of Stock and the only place that had them was Joe Bob's Outfitters (Black Dog mags), only $11.00 instead of $30.00 from CMMG (if they had them). They are the full size Mags for the AR15, not the stubbies with inserts. They are plastic, but work with absolute perfection. Being that the CMMG is a blow back design, the gas port/Piston is irrelevant. If its an old CMMG unit, you just remove the Gas Piston, but if it's a newer Evolution Unit, CMMG has already machined Bolt Carrier down, so you don't have to remove the Piston Rod. It's a beautiful Combination your going to love. Ps. It will shoot 3-5" groups at 100 yards, about the same as my Mini-14. What's really nice, the Sights do not need to be adjusted, it pretty much shoots dead on using the same setting as my 5.56 ammo. Hope this info helps. Jack B.

 

[jb2925]

For Jack and anyone else interested in the CMMG conversion kit I would like to share my experience. When I purchased my first AR I thought it would be nice to shoot the conversion kit, as my local rifle range has business hours, and my local indoor pistol range is open late and allows pistol caliber carbines. As I suspected, I had alot more opportunity to shoot the conversion kit in the evenings than the 5.56 during the day. What eventually ended up happening is that I fouled out my gas port and tube twice using the kit. if you are shooting one, make sure that you dont shoot more than a couple hundred rounds before running some 5.56/.223 through it. The .22 ammo doesn't have enough of a jacket or create enough pressure to keep the lead build up out of the port and tube. Now a couple hundred rounds sounds like alot, but when you are shooting low recoil CHEAP .22 ammo with a 50 rd drum mag it is very easy to shoot twice that much in one outing. Thats about what it took to foul it out the first time. I did this with a DI upper, and it was a pain to fix, It would seem to me that it may cause more trouble with a piston gas block if you got lead in it.
As far as the kit itself, it was great. The most fun I've ever had with my AR. The stainless kit cleans up great, and runs good with everything but Remington for some reason. Would I buy one again??? Probably not, and only because I love my Sig 522. I just thought I would share my experience to save someone else the pain of my mistake. If you use one of these kits, they are great, but just make sure you shoot some 5.56 frequently. If you don't you may want to get this routine down. Shoot..... pull charging handle..... shoot..... pull charging handle .......when the gun won't cycle cause the port is cloggged. Just my .02 Hope it saves someone a headache.

 

[Jack B]

Additional Info on CMMG 22lr Conversion for Sig 516

Thanks JB2925. Your absolutely correct. Depending on the Ammo your using, it does clog the Gas Port. Remington does seem to be the worst and CMMG advises against using it in their conversion kits. I can use about 200 rounds of Remington Ammo and when I switch back to 5.56, I'll usually have the first round fail to eject, but after that it clears itself and works fine. If I use CCI I can get 300-400 rounds before it clogs up. I've found Remington has a higher recoil impulse, which allows it to fire in just about any semi Auto, but it's much dirtier and clogs up the system faster. After some extended use, I've also found that Remington also clogs up (residue) on the inside of the Chamber adapter, causing you to get some really lousy accuracy. Groups will expand from 3-5 inches to several feet or more with just a hundred or so rounds being fired. I called CMMG and they said to polish out the Chamber adapter. I Simply dipped a wire brush in Brasso, fired up my electric drill for about a minute and problem solved. Now I can get at least 500 rounds out of it before things start clogging up again. In fact, CMMG now tells you in their Operating guide to polish out the inside of the Adapter. It seems anytime you want the convenience of an Adapter, no matter what make or model, instead of a dedicated Upper in 22lr, there will be some sacrifices to be made. Glad you brought that up JB2925. JackB

 

[Quest]

thanks for that info. I was planing to get the cmmg kit for my 516, but now it's going to be a complete upper or no kit at all.