I'm having trouble deciding on a .22 upper for a lonely lower in my safe.

1.  CMMG dedicated upper
2.  DPMS dedicated upper
3.  PSA PTAC upper with CMMG conversion kit


Any thoughts?  Which would you prefer?

Of the above, I use a dedicated upper (1x12 barrel) with a CMMG conversion bolt, therefore that is what I personally recommend.

Frequently forum members bring up the question as to how accurate are 22 LR conversions in AR-15's.  I decided to conduct a quick test to give an indication of the practicality of using a 22 LR conversion.  The biggest down side to using 22 LR conversions in AR-15's is the filth left in a centerfire rifle from shooting 22 rimfire.  A 22 conversion generally is not as accurate in centerfire 223/5.56 barrels because 22 rimfire bullet is .223 diameter and 223/5.56 is .224.  Rimfire ammo is usually shot in 1:15 or 1:16 twist barrels whereas my AR-15's are 1:9 and 1:7 twist.  Older AR-15's were 1:12 and some Wylde barrels use 1:8 twist.  

I decided to shoot five firearms today in this test.  All rifles were shot at 50 yards off my MTM bench using a bipod and rear sand bags.  All rifles were shot with the scope set on 9 power.  Below is a list of the firearms.

Savage Mark II FV heavy barrel with Famous Maker 3-9 AO scope.

DPMS 16" bull barrel Gen I with Tasco 2.5-10X44 scope.

KKF 16" 1:16 twist barrel with Ciener conversion, Tasco 2.5-10X44 scope.

Colt 20" H-Bar 1:9 twist 5.56
Chrome Moly, Famous Maker 2.5-10 AO scope.

PSA 16"  1:7 twist 5.56 Stainless Steel, 2.5-10X44 scope.

The only modification to the Savage was free floating the barrel and torquing the stock  to the proper spec.  The Colt, PSA and the KKF all have RRA NM trigger groups but the RRA NM went bad in my DPMS 22 LR.  I'm currently using a mil spec single stage trigger group which hurt the DPMS groups.

I decided to use the same ammo in each firearm and used five shot groups.  All shooting was done in one afternoon and the wind was blowing from the North east from 12-16 MPH with gust at 20+ MPH.  I was shooting southeast so there was a 1/4 wind value which didn't seem to affect groups.  Temperature was 75-80 degrees through the afternoon with 30.07 barometric pressure, 50% Humidity dew point 58 degrees.  The elevation is 450' ASL.

The ammo used in the test was shot in the following order in all firearms.

Eley Club 40 grain RNL standard velocity

CCI 40 grain RNL Standard Velocity

CCI Blazer 40 grain RNL High Velocity

Federal Game Shock 40 grain plated RN High Velocity

Aguila Super Extra 40 grain plated RN High Velocity.

I used an older box of Winchester Wildcats to sight in a couple of rifles.  The KKF and PSA used the same scope.  I used the same scope setting and was shooting for groups not particularly at the small black rectangle drawn on white 9" paper plates which was an aiming point.  I shot one group with the Wildcats in the PSA 1:7 twist barrel to show the variability ammo has on groups.

This is a picture of the Savage Mark II

 

Here is a picture of the DPMS Bull barrel Gen I AR-15.

Here is a picture of my KKF 16" 1:16 twist 22 LR, barrel has a modified barrel extension to accept any 22 LR conversion kit, I used a Ciener kit and BDM Mag today.




Another picture of the Kurt's Kustom Firearm 22 rimfire AR-15.




This photo is of the Ciener conversion and BDM magazine which was used in the KKF upper in the Colt and PSA AR-15's.





This photo is of the Colt 20" H-Bar, the Colt has a RRA scope mount which is the same mount used with the Tasco 2.5-10X44 scope which was used on the KKF & PSA.




This photo is of the PSA 1:7 twist SS rifle which used the Ciener conversion.

Now for the pictures of the targets.  This picture is of the target shot by the Savage.  The targets were shot in the following order, Eley Club center rectangle, CCI SV upper left, Blazer upper right, Federal Game Shock lower left and Aguila SE lower right.




This target was shot with the DPMS Gen I.  A standard mil spec trigger really hurts the potential accuracy of this rifle.  It shot a lot better with the RRA NM trigger.




This target was shot with the KKF barrel with Ciener bolt with chamber insert.

These Five pictures are the groups shot with Colt 1:9 twist chrome moly 5.56 barrel.

I shot the first five rounds of Ely club without cleaning the barrel which was fouled from shooting 223/5.56.  I shot a second group aiming at a staple for comparison to the very first five rounds of rimfire.  The last five of Eley club were shot after the Aguila.



CCI Standard Velocity 40 grain RNL.




CCI Blazer 40 grain RNL




Federal Game Shock 40 grain Plated RN HV.  This shot better than the typical 36 grain HP 550 bulk.  




Aguila Super Extra 40 grain plated RN High Velocity.  I shot a second group with the Aguila as the first group wasn't typical for how Aguila SE shoots in my conversions.  I used a different aiming point and the second group was better.  Conversions don't show the consistency of dedicated 22 LR uppers.

These six photos show the groups fired with the PSA 16" 1:7 Stainless Steel barrel with Ciener conversion.  Surprisingly I only experienced one stove pipe jam through the course of the hole day.  I normally don't shoot much standard velocity but it functioned 100% today.

The Eley Club, the PSA 1:7 is a new rifle with less than 20 centerfire rounds throughthe barrel.  I cleaned the PSA barrel prior to shooting the rimfire.




CCI Standard Velocity 40 grain RNL.



CCI Blazer 40 grain RNL High Velocity.



Federal Game Shock 40 grain Plated RN High Velocity.  I decided to shoot two groups as the first group wasn't that good.  I used a different aiming point and had five rounds at the top edge of the target.  There are three bullet holes right together.




Aguila Super Extra 40 grain plated RN High Velocity.




Winchester Wildcat 40 grain RNL.  I used this ammo to get a rough zero with the scope on the PSA and noticed it group pretty poor.  I shot this group to show what happens if your barrel does not like a particular brand/type ammo.






Even as bad as the Wildcats did in this group this would still be adequate accuracy for shooting CQB at steel targets at 25 yards.  The conversion kits work good enough to provide adequate accuracy for shooting paper or steel targets for CQB or plinking.

Most 5.56/233 barrels produce fliers which ruins groups when using 22 rimfire conversions.  I've used 1:12 chrome lined 20" 5.56/223 barrel with a Ciener conversion and depending on ammo it was a little better than my 1:9 twist barrels.  This was an A-2 upper with fixed carry handle so I didn't test it with a scope.  I've shot 22 rimfire through Stainless Steel 1:8 twist Wylde chambered 5.56/223 barrels and the results were similar to my 1:9 twist chrome moly and chrome lined 16" barrels.

No comparison for me. I first tried the CMMG bolt in my BCM 16" upper at 36 yards hoping against hope it would shoot well, but expecting it not due due to bullet diameter and barrel twist.  I was very disappointed as the groups were more like shotgun patterns with CCI Velocitor,  CCI Mini Mag, Augilla Interceptor and Fed AE being the most accurate.  My guns and I prefer 38 gr. or 40 gr. bullets.  Remington or Winchester anything shoot poorly in all of my .22 LRs and were also the worst in this test.

I then built a CMMG .22 LR dedicated upper using BCM upper components and Black Rain lower to match my 556 BCM upper/Black Rain lower rifle with both having POF 3.5# triggers, 15" Keymod handguard and Leupold 2-7x33 scopes.  This dedicated upper shoots as well or better as my other .22LRs and has an identical look, feel, groupings and point of impact as my BCM 223/556.  I could not be happier.  And it is a lot less expensive to shoot the .22LR with quality ammunition than it is the 223/556 with the same user experience, other than noise and recoil.

I bought a couple Chiappa M4-22 uppers.  Latest price I've seen around was about $150'ish, IIRC.  Came with 1 magazine.  You can use the black dog magazines with it, too.  Haven't really tested for accuracy, but they function just fine.

Thank you for the awesome write-up VASCAR2!  Thank you everyone else for your input!  Optics Planet had a good price on a dedicated CMMG upper with the "HOLIDAY" coupon code, so I Fo'd on it.

Glad you were able to make up your mind.  I have 2 CMMG uppers and they are as a reliable 22 rimfire can be and are loads of fun to shoot.  CMMG has great customer service if you have any issues.   I hope you enjoy your 22 AR's as much as I do mine.