M&P 15-22 vs. CMMG Conversion Kit

[paulleve]

I hit the range today to try a variety of cheap ammo through a 15-22 and CMMG conversion kit mounted in a 14.5" barreled AR. I forget the twist rate on the AR, so let's say it's 1/8.



Both rifles have red dots. The AR has a Sig Romeo5 mounted, and the 15-22 has a factory M&P red/green dot.


Groups were all 5 shots fired from 25 yards. The Romeo5 definitely had the advantage when shooting at the 3/4" dots. At the low setting I was somewhat able to see the orange dots. The M&P was a different story. The green dot was at least 2x the size of the targets, so some educated guessing was involved!

The CMMG target is on the left and 15-22 on the right. Each corresponding dot was shot with the same ammo. In general, the 15-22 groups were mostly about 1/2 the size of the CMMG. Both liked CCI Standard Velocity, and both didn't do so well with Mini Mags. Most of the 15-22 groups measure about 1". I'm sure both would do better with a little more patience, and some one of these weekends I may scope them both for a more accurate comparison.



Overall I have been impressed with the reliability of both setups. There was only one FTE today out of 200-300 rounds, and that was from the CMMG with a Mini Mag. That's the only failure this has had in about 400 rounds.

Here are my takes on both both setups:

CMMG
Good: Cost effective at about $135 shipped with a single magazine. Reliable, and just drops in. Can use this on the AR you already own with whatever upgrades you may have.
Bad: Not as accurate. Bolt release does not work with .22 mag. Your AR will get .22 LR dirty!

15-22
Good: Very reliable. I've put thousands of rounds of the cheapest ammo through it without any issues. Light, good for newbies. Controls all function like the real thing.
Bad: Not as easy to accessorize. More expensive at $400-500 depending on model.

 

[SKumar]

Great writeup. My experiences are the same with the CMMG bolt. However, I'm on a 16" barrel shooting at 50yds unsupported bench. At 50yds, I get about 2 inch groups. I won't push 22lr past 50 yds anyway.

I put together a dedicated 22lr throwaway upper: plastic handguard, plastic upper receiver, plastic sights, cheap barrel, etc. The whole setup cost maybe $350 including the CMMG bolt.

Although I think 22lr is an awesome cartridge, I'm not a 22 connoisseur just yet. I love casually plinking 22lr out of the CMMG until I'm ready to invest in a dedicated rig.

 

[xtry51]

We have both and use the CMMGs more often because they let you train with your primary rifle.

 

[mac1911]

Cmmg: hits on target type shooting
MP22 should group better proper barrel/rifling/twist

Red dots: not so good for shooting at tiny dots ,

all is good if your having fun

 

[Biff Quizler]

No brainer... M&P15-22. VERY reliable, accurate, light and fun.
I've had more than a few conversion kits, a dedicated .22 upper and now I have a M&P15-22
I learned alot with the kits and dedicated upper... including fine sanding skills and spring tweaking to get things to run well.

 

[JenkkiMike]

There is a third and best option but the cost is highest, a dedicated .22LR build. I recently put one together with a Taccom 4.5" ULW barrel and collar with a CMMG bolt and a dedicated lower with with the Better Mag Adapter that lets me use 15-22 mags that function with the last round bolt hold open. It's ridiculously fun to shoot with a Dead Air Mask and sounds like I am doing some light construction work out back with a small nail gun. In Mass where suppressors aren't an option the super short barrel doesn't make sense so I a 15-22 is probably the best and cheapest route.

 

[northny]

If you already have an AR, building a dedicated .22 rim fire upper is the way to go. As JenkkiMike said above the better mag adapter with 15-22 mags is the right set up. I built my first with a light weight barrel , second with CMMG barrel that mimics my ar in length and weight.

 

[murf4321]

I ordered a dedicated upper from them in March and it’s still back ordered.

 

[Whiskeywon]

I suppose either mentality. It's nice to have something that feels like a "real" gun in the conversions, but at the same time I'm never going to argue with the lightweight endless fun of a new gun either.
Glad to read your write up!

 

[paulleve]

I decided to try round two today in the cold, with scopes this time. The 15-22 had an Athlon NEOS 4-12x, and the AR was a 20" rifle with 1/7" rifling and Vortex Crossfire 2 4-14x. (I know, 1/7 is not good for .22, but 20" of barrel should have made up for it!) The goal of today's fun was to shoot a variety of bulk .22 and see how the CMMG conversion compares to the 15-22 under the same conditions.



Shooting conditions: Cold. Not the best for patient shooting! Five fouling shots of each were fired at various small pieces of clay pigeon on the berm, then a 5 round group was fired at 50 yards. Rifles were both roughly sighted for 50 yards with CCI SV. This is the first time a scope's been put on the 15-22, and the AR is used for 400 yard fun, so I didn't want to mess with zero any more than I had to.

The general results can be summarized as follows:
1. The 15-22 was more accurate with every round tested. CMMG group sizes were 10%-100% larger, with an average of around 50%.
2. The 15-22 shot about 2-4 MOA with bulk while the CMMG was about 3-6 MOA.
3. Both liked CCI SV and Mini Mags. The Mini Mags were the closest in terms of group size with both landing around 1.25".
4. Both shot largest groups with CCI Blazer and Winchester 333 and Super X. I'll skip these next time I see them on the shelf.
5. A few rounds were underpowered as evident in report and functioning. Two of these cycled the CMMG but failed to reset the hammer in the AR.

In closing: I'm really impressed with the functioning of both setups! That 15-22 goes bang every time no matter what bulk ammo I feed it, and the CMMG is totally reliable with the better quality bulk I've tried. Plus I was able to pop the CMMG kit out in about ten seconds and switch back to 5.56 for some slightly louder ammo tests.

 

[MGnoob]

The bolt release and forward assist work With the conversion if you buy the extra parts and do it right. The benefits to the conversion or as you can use it with the auto sear…. You could also do an entire upper replacement on a real AR 15 and achieve the same thing.

I will tell you Without the spring on the firing pin. You basically have an M 16. A run away one

I hit the range today to try a variety of cheap ammo through a 15-22 and CMMG conversion kit mounted in a 14.5" barreled AR. I forget the twist rate on the AR, so let's say it's 1/8.

View attachment 537925

Both rifles have red dots. The AR has a Sig Romeo5 mounted, and the 15-22 has a factory M&P red/green dot.
View attachment 537923

Groups were all 5 shots fired from 25 yards. The Romeo5 definitely had the advantage when shooting at the 3/4" dots. At the low setting I was somewhat able to see the orange dots. The M&P was a different story. The green dot was at least 2x the size of the targets, so some educated guessing was involved!

The CMMG target is on the left and 15-22 on the right. Each corresponding dot was shot with the same ammo. In general, the 15-22 groups were mostly about 1/2 the size of the CMMG. Both liked CCI Standard Velocity, and both didn't do so well with Mini Mags. Most of the 15-22 groups measure about 1". I'm sure both would do better with a little more patience, and some one of these weekends I may scope them both for a more accurate comparison.

View attachment 537927 View attachment 537926

Overall I have been impressed with the reliability of both setups. There was only one FTE today out of 200-300 rounds, and that was from the CMMG with a Mini Mag. That's the only failure this has had in about 400 rounds.

Here are my takes on both both setups:

CMMG
Good: Cost effective at about $135 shipped with a single magazine. Reliable, and just drops in. Can use this on the AR you already own with whatever upgrades you may have.
Bad: Not as accurate. Bolt release does not work with .22 mag. Your AR will get .22 LR dirty!

15-22
Good: Very reliable. I've put thousands of rounds of the cheapest ammo through it without any issues. Light, good for newbies. Controls all function like the real thing.
Bad: Not as easy to accessorize. More expensive at $400-500 depending on model.

 

[paulleve]

For anyone looking for additional magazines for the CMMG conversion, Bear Creek Arsenal has them on sale for $13.29 each. I ordered few and there was no additional charge for shipping.

 

[MGnoob]

I prefer the ceiner mags, but that’s because they’re 32-33rd (34 is to many) preban and metal.They do work well with Cmmg conversion though


View: https://youtu.be/xOrgLj9lOwk

 

[paulleve]

I picked up a Better-Mag adapter that allows 15-22 magazines to be used in a standard AR lower. The Better-Mag includes an aluminum insert that sits in the mag well, and an extension for the bolt catch that makes it functional with the 15-22 mags. I ordered this straight from the company for $46 shipped, and it arrived in only three or four days.




A CMMG adapter is already installed. Press the Better-Mag into the mag well, insert the bolt catch extension, and you're good to go.




I tried most of the .22 ammo I had in the range bag and had pretty good results. The bolt catch worked great, and held the bolt open on the last round every time. Some of the ammo was not so great.



The Automatch had multiple doubles, both with the 15-22 mags and the original CMMG manufactured ones. I tried the ammo in the 15-22 and it was obvious just how inconsistent it was. I was once again amazed at just how well the 15-22 handles every type of cheap ammo I feed it, even when you can hear that some of those rounds were way underpowered.

The Winchester 333 had problems in both rifles, much worse than I've experienced in the past. I wonder of the 9F temp was causing problems with whatever lube Winchester applies to these things.

Overall I'm really happy with the CMMG and Better-Mag combination. I't convenient to use the bunch of 15-22 mags I already have, and having a functional bolt hold open is a huge plus.

 

[Brad.in.IL]

I have a CMMG w/ 3 25-round mags and find it to be the pinnacle of reliability.

When I first bought the beast, I oiled it up really well, and took it to the range with 1,000 rounds of 22lr .. I kept shooting, and shooting, and shooting and shooting, trying to make it stop. After more than 700 rounds, I quit because I could not generate a stoppage. Yes, it was a dirty, filthy disgusting mess but with copper plated HV ammo, the damned thing just won't quit. And yes, it is a great way to train on the AR platform without the expense of "full house" .223 or 5.56 ammo. It's also a neat way to shoot an AR indoors without punishing your ears. My fave brand of .22lr to run through it? Aguila.

 

[B191299]

I have had good luck with the Cmmg Kit. Maybe not as accurate as a M&P 15/22 but it allows you to shoot your real AR on the indoor range.

 

[BRG216]

I’ve had nothing but trouble with my CMMG kit. My AR is super reliable but I can’t get through a mag of 22 without some issue. The biggest issue for me is the difference in zero for the optic. I don’t want to have to change my zero or holdover everytime I switch between 22 and 223.

 

[mac1911]

I’ve had nothing but trouble with my CMMG kit. My AR is super reliable but I can’t get through a mag of 22 without some issue. The biggest issue for me is the difference in zero for the optic. I don’t want to have to change my zero or holdover everytime I switch between 22 and 223.

There has to be a distance that your 223 “zero” and 22lr meet up ?
But asking a 3000fps and a 1000 fps projectile to match up is just …..silly

 

[paulleve]

There has to be a distance that your 223 “zero” and 22lr meet up ?
But asking a 3000fps and a 1000 fps projectile to match up is just …..silly

The two ARs I used in these tests were both close enough zero-wise to work well with the CMMG adapter without having to adjust scope/dot settings. The AR with the red dot is zeroed at 25m, and in .22 CMMG form is fine for plinking. The scoped rifle is currently zeroed at 400 yards, and at 50 yards with the CMMG I was within the 3" targets no matter the ammo I tried.

Different brands of .22 can group all over the place depending on brand and velocity. Even so, every type of cheap ammo I shot today was tin can accurate at 25 yards!

 

[mac1911]

The two ARs I used in these tests were both close enough zero-wise to work well with the CMMG adapter without having to adjust scope/dot settings. The AR with the red dot is zeroed at 25m, and in .22 CMMG form is fine for plinking. The scoped rifle is currently zeroed at 400 yards, and at 50 yards with the CMMG I was within the 3" targets no matter the ammo I tried.

Different brands of .22 can group all over the place depending on brand and velocity. Even so, every type of cheap ammo I shot today was tin can accurate at 25 yards!

Thats all you need then.