Best .22 LR conversion for an AR?

[Cameron]

I have been tossing around the idea for a .22 conversion that would drop into my 3 ARs and I was wondering who has any experience with the various options.

I would rather have a conversion than a dedicated upper so I can get the sights rails accessories etc.

I really have no idea where to start beyond a Google search.

Thanks,
Cameron

[jeffy]

The three major players in the drop-in 22 conversions are Ceiner, Spike's Tactical and CMMG. The original patent was given to Maxwell Atchisson back in 1973 (U.S. Pat. No. 3,776,095) and were sold through Colt. Jonathan Ceiner held the patent until recently and was the sole maker of the conversion for many years. Now the patent has become public domain so anyone can make them. If you want good customer service then go with Spike's or CMMG. There are currently two different CMMG kits and one Spikes out on the market right now.

CMMG makes their kit with a black finish as their main kit. There is also a stainless steel kit that's floating around as well. I think these were a special run sold through CDNN as I have not seen them sold elsewhere. Spike's Tactical on the other hand uses a nickle finish. They also have two small o-rings to the insert to help center the insert and seal any gases from escaping.

Here are the websites which list and sell the different conversions.



http://cmmginc.secure-mall.com/shop/index.php?shop=1&cat=81 - http://www.rainierarms.com/?page=shop/detail&product_id=1355
http://www.cdnninvestments.com/ar22stcokitw.html
http://www.spikestactical.com/z/index.php?main_page=product_info&cPath=26&products_id=176
http://www.22lrconversions.com/atch-pg.htm

[Cameron]

Jeffy thanks for the detailed reply, I appreciate the information.

I found the CMMG kit through Palmetto Armory with 3 mags for $180 here http://palmettostatearmory.com/sp6.php

I was told this is a good deal. What do you think?

Thanks again.

Cameron

[jeffy]

Jeffy thanks for the detailed reply, I appreciate the information.

I found the CMMG kit through Palmetto Armory with 3 mags for $180 here http://palmettostatearmory.com/sp6.php

I was told this is a good deal. What do you think?

Thanks again.

Cameron
Seeing as 3 magazine is a $60 option normally, I'd say it's a good deal. Those look like the CMMG mags and not the Black Dog Machine. I haven't heard of any issues with those magazines. CMMG seems to be the more prevalent kit out there, too.

[John Hwang]

Out of all the .22 kits I've seen, I really think the finish and work on the Tactical solutions dedicated uppers is the best.

[Eric]

My experience has been limited to the CMMG kit. (http://www.weaponevolution.com/forum/showthread.php?t=1300) I shot it again yesterday and had no issues. Remember that even though the drop in kit will work in all of your ARs, the POI is significantly altered.

[Quib]

My experience has been limited to the CMMG kit. (http://www.weaponevolution.com/forum/showthread.php?t=1300) I shot it again yesterday and had no issues. Remember that even though the drop in kit will work in all of your ARs, the POI is significantly altered.

Gas port blockage from lead build-up can be another concern.

[Narc]

I have had a CMMG kit for a few weeks and placed it into a dedicated AR. I have been very pleased with it so far. I have fired Federal bulk pack, Blazer 40grn, CCI Stinger, CCI Mini-mag, and Remmington Gold. I have had no failures to feed or failure to extract. I have had 1 round in every 150-200 out of the bulk stuff fail to fire. I think that is an ammo issue, as I have experienced that with my other .22lr's.

I only have used the CMMG magazines, but hear very good things about the Black Dog Machine ones.

[Cameron]

Gas port blockage from lead build-up can be another concern.

If the steel of a gas port is eroded over time, how can the lead stay there?

Cameron

[Eric]

If the steel of a gas port is eroded over time, how can the lead stay there?

Cameron
Because the .22LR does not deliver the same pressure as the .223/5.56. One way to keep it cleaned out is to install the standard BCG and fire off a few rounds of .223/5.56 after using the kit.

[Quib]

Because the .22LR does not deliver the same pressure as the .223/5.56. One way to keep it cleaned out is to install the standard BCG and fire off a few rounds of .223/5.56 after using the kit.

Yes Sir, that is correct.


Cameron,

I'm posting from the office at the moment. When I get home this afternoon I'll post a pic of the barrel gas port of my sons AR. It was completely blocked off due to lead build-up.

[jeffy]

Check your gas port or shoot 5.56 occasionally to clean it out. It's not a big deal if you're not shooting exclusively 22LR. In which case you would then benefit from buying a dedicated upper with the correct barrel twist.

[Quib]

Here are the photos I mentioned earlier today, showing the lead build-up in my sons carbine.

Now this is an extreme case, where a few thousand rounds of .22 was fired during training, and no .223/5.56mm fired occasionally to purge the gas system of lead.

But this is an example of what could happen if the lead build-up is not taken into consideration.

I shot these pictures a few years ago during the tear-down and rebuild of my sons carbine after I replaced the M261 .22 conversion kit with a standard AR15 bolt. I figured some lead build-up might be present, but never expected the amount that I discovered.

The barrel gas port had to be cleaned using a metal dentists pick. The FSB and gas tube had build-up as well, and required the use of a mini-torch to get the lead to drip free.

http://farm3.static.flickr.com/2620/4112740373_c81c8ccbee_o.png

http://farm3.static.flickr.com/2546/4113508784_ea404cde07_o.png

[Cameron]

So would a few rounds of 5.56 clean that out?

I bought the CMMG kit last week, I should have it this week and let you guys know how it functions.

Cameron

[Quib]

So would a few rounds of 5.56 clean that out?


Nope. There’s no way firing 5.56mm/.223 would have cleaned out that amount of build-up. It was solid lead from the barrel gas port, through the FSB gas passage, and into the gas tube. The whole gas system was sealed shut.

[jeffy]

So would a few rounds of 5.56 clean that out?

I bought the CMMG kit last week, I should have it this week and let you guys know how it functions.

Cameron

If you shoot a box of bulk then shoot some 5.56 afterward it shouldn't be a problem. If you predominantly shoot .22LR and don't shoot 5.56 then you should clean your barrel and check for blockage after ever brick. If you use jacketed bullets then you should be able to stretch it a bit.

As Quib pointed out already, his is an extreme case of neglect. If you want to shoot 22lr exclusively then you should buy a dedicated upper.

Spike's Tactical conversion comes with a plug that can be used to replace the gas tube if you don't plan on using it with 5.56. This keeps the carbon from building up in the gas tube but will not prevent lead buildup.

[Spectre1]

If you shoot a box of bulk then shoot some 5.56 afterward it shouldn't be a problem. If you predominantly shoot .22LR and don't shoot 5.56 then you should clean your barrel and check for blockage after ever brick. If you use jacketed bullets then you should be able to stretch it a bit.

As Quib pointed out already, his is an extreme case of neglect. If you want to shoot 22lr exclusively then you should buy a dedicated upper.

Spike's Tactical conversion comes with a plug that can be used to replace the gas tube if you don't plan on using it with 5.56. This keeps the carbon from building up in the gas tube but will not prevent lead buildup.


This build up, and the improper rifling twist of a "real" AR, is what led me to my purchase of the S&W M&P 15-22. I have been quite pleased with it and I am sure it will make a great trainer.

Just my two cents. YMMV.

[austin12gauge]

I have been using a CMMG kit in my N4 for about a year now. I had ammo problems at first (Remington Goldens) but I quickly switched to Federal #750 bulk pack. Since then, about 5,000 rounds later, I had had no failures to feed, fire or extract whatsoever,

I usually shoot 200 to 400 rounds of 22 per session and always follow it with with no less than 5 XM193 at the end. I have not experienced any function problems with 5.56 whatsoever and I would expect some if the gas port/tube was partially blocked.

[Cameron]

Mine should be here this week, and it will not be a dedicated .22 trainer either i will probably shot 200-500 rounds of .22 and then switch back to .223 anyway.

Sounds like everyone is having good results I am looking forward to trying it out.

Cameron

[NOLACOPUSMC]

I have been shooting the Spikes kit for a about a year. got probably 500 rounds through it with no problems. I like the BDM magazines. Spike's customer service is pretty damn good. I got the kit when they first came out and their was a production error that needed to be fixed. they had it back to me in about a week and threw in a free magazine for my troubles.

Does anyone know which of the dedicated 22 rifles take the BDM magazines?