CMMG .22 conversion unit for AR-15

[seagiant]

Hi,
Was wondering if anyone has used one of these?

[dsbock]

I have the stainless steel version.

Drops right in place of the bolt. Functions just like it should (accuracy will vary with load and barrel twist) and comes right out at the end of the day. I use mine in a retro style (faux) XM16E1 with a 1/12 twist barrel and a (faux) XM177E2 with a 1/9 twist barrel.

What else would you like to know?

David

[Woody3]

I have one too. Talk about money well spent!!! Cheap to shoot and very fun to boot. My daughters 5&3 love to shoot it off a rest with stock collapsed. It's also a good way to practice (run n gun) techniques.
Hope this helps make up your mind.


Keep your head low and your powder dry.

[seagiant]

Thanks Gentlemen,
I think the SS CMMG unit is the way to go. Spikes Tactical used to make one but is now concentrating on dedicated 22 LR uppers. I just wanted to makes sure everyone was happy with the CMMG brand! My rifle has a 7:1 twist,does anyone know the best twist?

[Doc Highwall]

I have 2 of the Spikes Tactical dedicated 22 LR uppers. and the twist is 1-16".

[dsbock]

My rifle has a 7:1 twist,does anyone know the best twist?

Seagiant,

1:7 twist may be too fast to properly stabilize 30-40 grain .22LR bullets. 1:9 is marginal with the lighter weight. 1:12 or slower is usually considered optimal.

That being said, every rifle is different. My 16" 1:9 barrel is almost as accurate as my 20" 1:12 barrel.

Best thing to do is buy (or borrow) a CMMG conversion unit and try it out. If it works, great, if not, you justified getting another AR. Win-win.

David

[Larry Gibson]

Seagiant,

1:7 twist may be too fast to properly stabilize 30-40 grain .22LR bullets. 1:9 is marginal with the lighter weight. 1:12 or slower is usually considered optimal.

That being said, every rifle is different. My 16" 1:9 barrel is almost as accurate as my 20" 1:12 barrel.

Best thing to do is buy (or borrow) a CMMG conversion unit and try it out. If it works, great, if not, you justified getting another AR. Win-win.

David

+1.

While I don't have a CMMG conversion I have a military M261 conversion and have used it extensively in 12, 9, 8 and 7" twist ARs. The 12" twist .223 AR barrel is the best twist for use with the conversion bolts in standard ARs (a 16" twist is best for the complete upper conversion). The 9" twist is the next best as far as accuracy is concerned.

The 8 and 7" twist become ammo sensitive with the ultra high speed .22LR ammo giving poor accuracy results most of the time. Some regular High speed 40 gr ammo will shoot fairly well. Standard velocity or the heavier bulleted subsonic ammo most often does the best in the faster twists. Thus if you can test and then purchase a large quantity of ammo the 7" twist is ok. However if you want to use whatever 22LR ammo is avialable at the moment then a 12" twist barrel is what you want. I prefer the 12" twist anyway for my AR as I use M193 or reloads of 50 - 55 gr weight bullets anyway. 60 gr cast also does very well in the 12" twist.

Larry Gibson

[seagiant]

Thanks Gentlemen,
I might have to go to a dedicated upper! Spikes Tactical is 30 minites down the road so might be something to look into! I like my 1:7 twist barrel for the 62 gr. pulled surplus bullets! Oh well,can't have it all! Thanks again!

[garym1a2]

I don't think spikes makes them anymore

[Jailer]

Got one and it works great. Minute of pie plate accuracy at around 30 to 50 yards can be expected.

I also have a M&P 15-22 and really love that gun. I haven't touched my conversion since I got the 15-22.

[Doc Highwall]

My 2 dedicated 22 LR uppers will keep the shots in a clay pidgin at 200 yards.

[shotman4]

200yds for a 22 lr give 4 asprin and a 1/5 of jim beam
the unit works good with the aguila SSS its not much good at 200yds . but at 50 is real good in the fast twist

[beex215]

shooting the conversion in a 1/7 twist barrel resulted in 2-3 inch groups at 30 feet for me.

[wellfedirishman]

I have a couple of the CMMGs and they work great. With 1/12 twist barrel, they are decently accurate (2 inches offhand at 50 yards). With 1/9 twist, that opens up a bit to 3-4 inches which is fine for plinking.

They are a whole lot of fun and cheap to shoot. Just make sure to fire a few rounds of 223 when you are done shooting 22lr to keep the gas tube clean.

[dk17hmr]

I picked up one of those Chiappa 22lr uppers. It seems pretty accurate. I need to put a red dot or a scope on it and go chase some rabbits with it. Seems like I gave less than $275 for the complete upper and 2 mags.

[Larry Gibson]

shooting the conversion in a 1/7 twist barrel resulted in 2-3 inch groups at 30 feet for me.

That is fairly typical, especialy with HS .22LR ammo. Did you try any subsonic 40 gr lead solids? Or the heavier 60 gr sub sonic Aquila?

Larry Gibson

[shotman4]

one thing about the 60gr aquila is unless you modify a spring it wont eject auto. I took another spring and started cutting some off. Just make sure you dont change back to reg HS ammo with the light spring