Let me start by saying I don't need one. I already have a complete rifle (S&W M&P15-22) to complement my Ruger AR. It feels, handles and has identically operating controls to an AR. Having said that, these appear to consist of a replacement bolt carrier group and a magazine. But if you slip this into your upper, you're still using a 1:7 to 1:9 rifling twist (.22LR twist is 1:16), are you not? The accuracy can't be very good. Just curious.

Potential issues with the conversion kits:
- Twist rate, as you noted.
- The bore of a .223 Remy is about .001" larger than that of a .22lr. 22lr accuracy is rarely good from a 223 Remy upper.
- Fouling, which affects certain guns more than others. 22lr ammo is quite dirty. Many 22lr bullets are not copper coated. Firing 223 Remy ammo -- after extended 22lr use, without cleaning the 223 upper -- might cause cycling issues.

Dedicated 22lr uppers for AR15s exist, although they cost more than the 22lr conversion kits.

I recently bought one of the CMMG kits that Brownells had on sale for $179 and I had a $20 coupon. I put it in a 10.5” Aero sbr and shot 200 rounds at my local indoor range. The distances were 15 and 30 yards using a variety of 22 ammo. It was just damn fun! Accuracy wasn’t bad, definitely not precision bolt gun or anything. I had a couple of failures to fire with random bulk pack 22, but really no more than when I shoot my MKIV.
I went into it not expecting much was pleasantly surprised. The one tip I read was run a round of 5.56 through it every couple hundred rounds to blow out the crap.

quote:

Dedicated 22lr uppers for AR15s exist, although they cost more than the 22lr conversion kits.

I imagine they'd rival, if not exceed, the cost of an entire M&P ($325 in 2019, no telling what they are now).

Interesting about the .22LR vs. 5.56 bore diameters. I didn't know that.

Those "adapters" are shit. They can be fun, they turn 22's into noise and flash, but they are shit. The twist rate is all wrong they can lead up your gun and gas port, they aren't very accurate, etc.

The dedicated uppers are also fun. They are also as accurate and reliable as you can make them. I have 2, both made originally by Spikes. They are as accurate as any 22 rifle I own ( I don't own any "target" rifles.) They feel identical to your AR because they are identical except for not having a gas tube.

They aren't cheap, not crazy expensive either. I find them to be great fun.

My CMMG kit is used in conjunction with a PSA 16” upper. I use it to shoot steel plates out to 50 yards. Accurate enough to hear them ping off the plates.

About every 300 rounds I shoot between five to ten rounds of 5.56/.223 through to clean the gas system. So far so good.

Put it on paper at 50 yards and its not very impressive. They are toys. Fun but toys.

Try a Smith & Wesson M&P 15-22

They work great and are accurate. Mrs. Flash has one.

15-22's are fun. They make a braced pistol that looks even more fun.

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They make a braced pistol that looks even more fun.

maybe for a few more days?
In any case the conversions don't work very well except for fun plinking in which case they work fine. The S&W is a real bargin, but if your goal is running something that approximates your real gun then they are not particularly good for that.
I've run the CMMG and the TACSOL uppers for lots and lots of rounds and been very happy.
All fwiw.

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Originally posted by egregore:

quote:

Dedicated 22lr uppers for AR15s exist, although they cost more than the 22lr conversion kits.

I imagine they'd rival, if not exceed, the cost of an entire M&P

The cost depends on the upper. In my case, noticeably more than an M&P. It all depends on one's goals for the upper.

My first 22lr upper is a JP Rifles 18" barrel. It is absolutely a match grade semi-auto. Its accuracy even hangs with many accurate bolt action 22lr rifles. Here's a .81" 5-round group on a 4" plate at 100 yards using Wolf ammo, from prone. My notes state that winds were 4-7 mph from the right, which means I held off the right edge of the plate an inch or two, level with the bottom of the bolt.



I recently bought a Nordic Concepts 9" upper. I have not yet done much accuracy testing -- really just zeroing at 40 yards. The upper holds promise with accuracy, but it won't match the JP. I will primarily shoot the Nordic offhand, while moving between multiple targets. Here's from the first day out, showing 5 of the targets I set up in this training ravine.



My 22lr uppers serve as alternatives to training with my 223 uppers -- which must be described as very accurate. My 223s are match rifles, and thus my training uppers must also be up to the task.

I bought a conversion kit from Brownells, after three or four consecutive jams I gave up and sent it back. Yeah, it may have been operator error.

Bought the Walther/Colt model from CDNN for $300 four years ago, it shoots great. They're now real hard to find, here's one that's out of stock:

https://www.brownells.com/fire...60300-prod93428.aspx

I used to practice my offhand (Service Rifle shooter) at the local indoor range with a basic A1 rifle, and a M261 conversion, (1x9 twist barrel) and keep all the rounds in a 2 inch sticker at 25 yrds,

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Originally posted by Sigmund:
I bought a conversion kit from Brownells, after three or four consecutive jams I gave up and sent it back. Yeah, it may have been operator error.

It took about a hundred and fifty rounds through mine to loosen up enough to reliably fire, stove pipes were the majority of the problem but it did also have a couple failure to feed but I’m pretty sure that was due to the magazine needing some wear in. I’ll admit I had second thoughts about mine also but not anymore.

Made it this far with no mention of Tippmann Arms?

I bought one of the 16” Bear Creek .22LR uppers a little over a year ago (I also have the CMMG conversion kit)…the CMMG kit functions pretty much up to par with any ammunition except Remington Thunderturds or newer Winchester bulk (older Winchester bulk still is pretty much trouble free)…I know Bear Creek gets shit on in reviews …but function and accuracy has been great…the CMMG conversion does fall pretty short in the accuracy dept. due to the 1-8” twist…the BCA upper’s accuracy is up there with my SIG 522 and my brother’s S&W MP .22…I think IIRC I paid $269 for the BCA upper with one 10 round mag with free shipping…I’m satisfied with it.

In honor of this thread I took my 16” Spikes Tactical 22 upper along to the range today. I put a Leupold 1.5-5x variable on it and sighted in. My best 10 shot group was all 10 in the X. That’s good enough for me at 50 yards. I was shooting a literal mixed bag of different bulk pack ammo. The uppers are very capable units.

The flash hider on my Nordic 9" upper was torqued down uber hard from the factory. Took the upper to my local 'smith to remove it. He had to remove the handguard, place the barrel in a vice, and grab the Magpul AR wrench. All good now, nice and quiet with a Thunderbeast rimfire can.



I re-zeroed at 40 yards, from a standing position with a solid tripod. I might be able to obtain a little tighter groups from prone with bipod or bags, but I have a decent feel for the upper's accuracy. Probably 1-1/2 MOA or less at shorter ranges, with Wolf Match Target. Printed groups of 9/16", 3/4", 9/16", 11/16" and 1/2". Experiencing a few light strikes with Wolf ammo -- hopefully this goes away.

This thing is a bunch of fun to shoot at arrays of steel targets.