.22 LR - CMMG conversion kit or dedicated BCA Upper?

[12Bravo20]

so I am thinking the barrel doesn't like the plastic ATI upper. Going to put it in a PSA upper and see

I would say that you are correct.

I bought a Chiappa 22lr upper years ago and accuracy was nothing to brag about with the M4 hand guards and polymer receiver. The accuracy went way up once I switched to an aluminum receiver and a free float hand guard. The upper while not as accurate as my home built upper with a CMMG 16" heavy barrel or my Savage MkII, it is as accurate or more than my best Marlin Model 70 and Romanian M69.

 

[maxxhavoc]

I would say that you are correct.

I bought a Chiappa 22lr upper years ago and accuracy was nothing to brag about with the M4 hand guards and polymer receiver. The accuracy went way up once I switched to an aluminum receiver and a free float hand guard. The upper while not as accurate as my home built upper with a CMMG 16" heavy barrel or my Savage MkII, it is as accurate or more than my best Marlin Model 70 and Romanian M69.

Interesting - The ATI and Chiappa M4-22s were the same. I actually bought the CMMG barrel and bolt to fix the inaccuracies (and incorrect clocking of the front sight) of the ATI/Chiappa.

If the upper fixes it, maybe I'll put the ATI gear back on and see how it does.

 

[12Bravo20]

If the upper fixes it, maybe I'll put the ATI gear back on and see how it does.

Going with an aluminum receiver and a free float handguard fixed my issue with the Chiappa upper. It has proved to be pretty accurate after the changes.

 

[cfullgraf]

I have two dedicated 22LR bolt system/barrel AR-15 rifles.

The first is a DPMS upper based on the old Colt bolt system. It is a 22LR "A2 copy" of my 2005-ish Compass Lake Service Rifle match rifle for primarily inexpensive rapid fire practice drills.

The other is a 16" dedicated BCA assembly/22LR barrel built around 2015.

Both are noit match grade accuracy but provide adequate accuracy for plinking and casual small critter control. When I built the DPMS rifle, reports on the conversion kits were not very stellar on accuracy. So, I avoided them but they do have their purposes.

Over the years of shooting firearms that have interchangeable components to change cartridges or barrel length, I've decided I'd rather have a complete firearm as opposed to a single frame that I swap out the "upper" when I want to shoot a different configuration. It always seems the gun is set uo for the "wrong" cartridge that I wish to shoot that day.

I have a number of T/C Contender frames mated to particular barrels and I have no AR-15 uppers that do not have a dedicated lower for them.

I'll agree that not everyone wants to or is willing to spend the extra money on a firearm that can be easily converted to a different cartridge.

 

[maxxhavoc]

Not sure I can recommend the CMMG dedicated kit barrel. I was trying to get the accuracy better than 20moa or so, looks like it is the barrel crown. There is a definite lip going into the lands and grooves at the muzzle, as well as some tool damage of some kind.

 

[herrwalther]

I recently bought the CMMG conversion bolt, within the last year. Farthest I have shot it so far is about 50 yards and it is close enough to my 5.56 zero to be a decent plinker. Or trainer rifle leading up to the real caliber. Total rounds through is about 1000, with no reliability issues so far. Works well enough for me that I am considering offloading my bone stock Ruger 10/22 to make safe room for something else.

 

[LiveLife]

Will plan a three-way 50 yard group comparison on next range trip for CMMG conversion bolt in 1:8 AR barrel vs BCA dedicated upper in 1:16 vs 10/22 or T/CR22 in 1:16 comparison - https://www.thehighroad.org/index.p...ar-upper-50-yard-groups.932322/#post-12943971

Range Report:

• T/CR22 - 18" Green Mountain bull barrel 1:16 - Volquartsen Target Hammer kit (2 lb trigger pull) - Magpul MOE X-22 Stock - Vortex Strike Eagle 4-24x50
• BCA 16" 22LR upper 1:16 - Bushmaster lower - Timney Impact trigger - Athlon 10-40x56
• CMMG 22LR conversion bolt - 20" .223 Wylde 1:8 - Bushmaster lower - Timney Impact trigger - Athlon 10-40x56

In "Real World" sense, T/CR22, BCA 16" and 20" .223 Wylde barrels all have several hundred rounds shot through without cleaning (Muzzle crown was cleaned for testing). Aguila 40 gr CPRN "boxed" ammunition used for testing. (I plan on repeating the comparison test after cleaning barrels)

Top Row: T/CR22 GM barrel groups measured 3/8", 3/4", 3/4", 1/2"
Middle Row: BCA 16" upper groups measured 7/8", 2.25", 1.25", 2"
Bottome Row: CMMG conversion bolt groups measured 2", 1.75", 1.75", 2.25"

Will also report on feeding/reliability of CMMG/Black Dog AR22 magazines and extraction/ejection that some THR members have posted about BCA 22LR upper in years past.

No feeding/reliability issues using Black Dog AR22 magazine. All rounds fired on first primer rim strike.

 

[tbs]

I picked a CMMG conversion kit about 6 months ago. I am using it in a 1 in 7 twist upper with satisfactory results. Here is what I have discovered using this conversion kit. If you have one of those 3.5 lb. cassete triggers you will get tons of light strikes. I switched out my trigger for an ALG ACT trigger using the 4.5 lb. spring and it works perfect. Using the standard charging handle caused tons of cases to get stuck in it when ejecting. I added the CMMG charging handle and problem solved.
The conversion kit did not like mini mags or any high velocity stuff but runs great with CCI standard velocity and has better accuracy. After a bunch of trial and error I got this thing running flawlessly.

 

[4v50 Gary]

Dedicated for greater accuracy and less leading.