AR .22 LR conversion

[PappyM3]

I have a 16” light weight CMMG barrel build for plinking with kids, but I haven’t checked its group yet.

However, I also had a CMMG 16” Bull barrel laying around and some other spare parts. So I’m putting that together to hopefully have a precise 22lr gas gun. We’ll see. I will be putting it on my CMP Service Rifle lower, but haven’t actually assembled it yet and will be putting a Harrel’s Precision tuner brake on it. Also, thinking maybe WWII OD green for a paint job?

View attachment 662736

Lapped the receiver, bedded the barrel, and got everything setup aside from the muzzle device. First coat on and hopefully I’ll make it out to the range Monday or Tuesday for zeroing, velocity check, groups and getting DOPE at 200. As long as it groups well, I’ll be taking it out to Granby next weekend.

I’m going to try Lapua Center-X and CCI Subs.

 

[paul73]

Lapped the receiver

i`ve never given much credit to that before, but, now i am a true believer and do that religiously. it truly makes a ton of the difference, believe it or not, explain it or not.

just out of curiosity - what scope it was in its virgin form?

 

[paul73]

I’m going to try Lapua Center-X and CCI Subs.

if it will cycle it well - you'd be a lucky one. i shoot those both ARs on minimags and aguila se, none of subsonic ammo i have cycles `em well.

also - for the cmmg bolt make sure to put some plug into the buffer, so it would be pressing that assembly forward a bit. it helps a ton.

CMMG 22 .22lr Buffer Plug Improve Reliability Plug | eBay

This simple buffer to plug is to be used with your CMMG 22LR conversion kit. It will put increased pressure on the back of the CMMG bolt and therefore greatly improve reliability. This goes great with our CMMG speed loader and CMMG case!

www.ebay.com

 

[PappyM3]

if it will cycle it well - you'd be a lucky one. i shoot those both ARs on minimags and aguila se, none of subsonic ammo i have cycles `em well. also - for the cmmg bolt make sure to put some plug into the buffer, so it would be pressing that assembly forward a bit. it helps a ton.

CMMG 22 .22lr Buffer Plug Improve Reliability Plug | eBay

This simple buffer to plug is to be used with your CMMG 22LR conversion kit. It will put increased pressure on the back of the CMMG bolt and therefore greatly improve reliability. This goes great with our CMMG speed loader and CMMG case!

www.ebay.com

We’ll see. Maybe I’ll bring some CCI ARs too. My old M&P 15/22 loved those.

The CCI subs aren’t the “quiet” ones with a super low FPS. I think they’re over 1000 fps, so hopefully worst case I’ll just need to cut a couple coils off the recoil springs. I mostly just want to avoid going transonic.

I don’t really have reliability issues with my CMMG BCG, with normal buffer and spring still in there, and using the better mag adapter and M&P mags. But I’ll have to try one of those buffer plugs. Thanks.

i`ve never given much credit to that before, but, now i am a true believer and do that religiously. it truly makes a ton of the difference, believe it or not, explain it or not.

just out of curiosity - what scope it was in its virgin form?

A really crappy Vortex Diamondback Tactical 4-16(14?). Ha, the handguard cost more than the scope. But, it has an easy to use MRAD tree and the parallax can focus pretty close. I got it as a cheap optic to check load development groups on my LPVO rifles, but I think it might live on this upper for a while. Might change it out for a 2.5-10 down the road, but not anytime soon.

 

[PappyM3]

i`ve never given much credit to that before, but, now i am a true believer and do that religiously. it truly makes a ton of the difference, believe it or not, explain it or not.

I’ve never personally measured improvements, but it’s quick and easy to do. And I can clearly go from some minor wobble to none. Worst case, even if it doesn’t improve consistency, it should make sure the barrel is inline with the receiver for better zeroing.

 

[PappyM3]

Mk12 Mod 22 ready for testing.

I would have gone with a more correct riser rail, but the “correct” ones don’t offer the 20 MOA cant that this one does. And I went with a tuner brake instead, because of how different lots of 22lr can have such varied performance.

 

[PappyM3]

I did a work up today, testing some varieties with some adjustments to the tuner brake. What kinds of groups are people getting with 22lr out at 100 and 200?



I tried:
* Lapua Center-X
* CCI Subsonic
* CCI AR Tactical (only one that was actually supersonic)
* CCI Standard Velocity Target

I know there are other match options from other brands, but this is what I had on hand. Does anybody know where to get Eley or SK locally?

They all cycled perfectly fine and didn’t have a single malfunction in the 150 rounds fired. They even all locked back on empty with the “better mag adapter” and M&P mags.

Turns out Center X was the top in precision, with CCI SV Target coming second. None of them were bad for normal 22lr plinking fun. You can ignore the center bullseye, that was for zeroing.



Things with Center X started out decently, with a .646 MOA 5 shot group and a .96 MOA 10 shot group with two called pulled shots at 50 yards.



But then it went to crap at 100 and 200 yards. Vertical stringing really opened up the groups.

But none of the vertical stringing were called. I ran out of time for the chrono and will have to get extreme velocity spreads another day. The calculated average velocity based on the 50 and 200 yard impacts is 1008 FPS.

100 yards opened up to 1.782 MOA, but the windage was still only 3/4” MOA. 200 yards opened up to 3 MOA, but the windage was 1 3/4 MOA.

 

[paul73]

What kinds of groups are people getting with 22lr out at 100

ARs i have did not do much better at a 100 than yours did. i can try to retest it.
For the 100yds the only decent shooter i have is a cz 457. here is my last test thread:

a 22lr ammo comparison for cz457 mtr varmint

so, as i do not have a vudoo yet that shoots any shitty loads through a same hole at a klick distance simultaneously spurring rainbows from its buttstock :) - i need to confirrm my baseline from time to time. mostly because i got 2 cases of newish norma tac22 in red boxes and wanted to confirm...

www.northeastshooters.com

Midway had SKs, but too expensive. I’ll keep shooting Norma there. Dunno if Norma would cycle my uppers.

 

[Cap'n Mike]

Mk12 Mod 22 ready for testing.

I would have gone with a more correct riser rail, but the “correct” ones don’t offer the 20 MOA cant that this one does. And I went with a tuner brake instead, because of how different lots of 22lr can have such varied performance.

View attachment 663290

That is fricken awesome.

 

[PappyM3]

ARs i have did not do much better at a 100 than yours did. i can try to retest it.
…

Do you remember if it was overall precision, or if it had similar vertical stringing? One hypothesis I have is that the CMMG bolt isn’t consistent enough in its blowback. Because it seems like the barrel is capable of sub-MOA. The ammo can clearly do that precision too, and I would hope Center-X wouldn’t have a 40 fps extreme spread. .. who knows, maybe it does.

 

[paul73]

Do you remember if it was overall precision, or if it had similar vertical stringing? One hypothesis I have is that the CMMG bolt isn’t consistent enough in its blowback. Because it seems like the barrel is capable of sub-MOA. The ammo can clearly do that precision too, and I would hope Center-X wouldn’t have a 40 fps extreme spread. .. who knows, maybe it does.

There was vertical stringing, yes. I will take those uppers with me next week to try.
Best group from cz at 100 was .79moa, I think. I do not expect to see better than 2 moa from ARs.

 

[PappyM3]

That is fricken awesome.

Thanks. It was a fun build.

 

[DW357]

I know there are other match options from other brands, but this is what I had on hand. Does anybody know where to get Eley or SK locally?

Not local but MSS has some SK and Lapua. There's a $10 off $100 orders and $25 off $250 order coupon that ends tomorrow night. 17 cents for the SK before the coupon
Nice shooting BTW

 

[PappyM3]

Not local but MSS has some SK and Lapua. There's a $10 off $100 orders and $25 off $250 order coupon that ends tomorrow night. 17 cents for the SK before the coupon
Nice shooting BTW

Thanks. I’m pleasantly surprised with the potential that the CMMG 16” Heavy Taper barrel has. Shame they don’t sell it anymore as it was a lot cheaper than the other 22lr AR match barrels on the market. Aside from maybe the JP, since that comes with the bolt.

 

[paul73]

Thanks. I’m pleasantly surprised with the potential that the CMMG 16” Heavy Taper barrel has. Shame they don’t sell it anymore as it was a lot cheaper than the other 22lr AR match barrels on the market. Aside from maybe the JP, since that comes with the bolt.

i had too much stuff to do today so did not get deeper into that.
here is what i got - CMMG is on the left, BCA on the right, both are 16", shooting norma tac22. aguila se did some ridiculous like a 1ft wide group, i did not care to troubleshoot what the heck was that, just shoot some normas. BCA grouping is also retarded, dunno what gives - like 4 subgroups in the group. weird.
but i was running late, so, did not even try to sort it out. target grid is 1".



compared to the CZ 457 it is all a huge pile of crap anyway, as here is how it is supposed to look like - 10 shots at same 100yds, same norma tac red box.
POA was that red smudge - the left corner of the yellow rhombus.
both ARs above are really fun for 50yds, where it groups into a 1" circle, and it is fine with me.

 

[PappyM3]

i had too much stuff to do today so did not get deeper into that.
here is what i got - CMMG is on the left, BCA on the right, both are 16", shooting norma tac22. aguila se did some ridiculous like a 1ft wide group, i did not care to troubleshoot what the heck was that, just shoot some normas. BCA grouping is also retarded, dunno what gives - like 4 subgroups in the group. weird.
but i was running late, so, did not even try to sort it out. target grid is 1".

View attachment 664709

compared to the CZ 457 it is all a huge pile of crap anyway, as here is how it is supposed to look like - 10 shots at same 100yds, same norma tac red box.
POI was that red smudge - the left corner of the yellow rhombus.
View attachment 664710

Much appreciated.

I think my barrel is capable of better groups at 100 than I saw, so I’ve come up with a smattering of things to try:

- I ruled out sorting ammo. It doesn’t seem to do much for match ammo

- I got that buffer plug you linked and will see if the persistent pressure on the bolt will provide more consistent velocity

- I’m putting on a bubble level and also double checking my scope mounting

- I’m going to do a more thorough Hopewell method of tuning my brake. I only went until I saw a good group and turning it more resulted in a worse group.

- I was going between ammo brands and apparently that’s a no-no with 22lr. So I’m going to bore snake my barrel, get a few fowling shots and stick with one brand.

- I’m going to remember to bring my rear bag

- I’m going to bring my chronograph next time and get actual data on extreme spread and SD of velocities

I don’t have time or desire to burn through ammo to test each thing individually, so I’m going to do all the changes and once and see what comes out. Maybe I’ll do the buffer plug separately with the chronograph because I am curious if that will actually affect velocity consistency.

 

[PappyM3]

Man, rimfire is frustrating.

I fixed a scope level issue and did a more thorough tuning of my brake. I pretty much got the vertical dispersion down to about 1 1/4 MOA at 100 and 2 MOA at 200. It was a bit windy today, so don’t mind the windage variation. Basically shaved 1/2 MOA from my vertical at 100 and shaved 1 MOA off my vertical at 200.

First I did a gross tune of the brake, and then narrowed down to a small range.

The big problem is that I had the elevation pretty solidly on point at 100, but when I went to do a confirmation group, everything was suddenly .2 mil low. No f***ing clue why. I made zero adjustments. I had gone down range to add an additional target sticker, and it’s almost like someone adjusted my scope while I was down range.

I know this upper can occasionally do good groups, but I have zero confidence in its repeatability.




This “1.9” (labeled for the elevation used at 100) group below was shot right after all 12 of the 1.5” yellow targets above, with no adjustment made to the scope. WTF? I had parallax set properly and my holds were within the 1” yellow target.



200 seemed okay. Better than before.

 

[paul73]

Man, rimfire is frustrating.

I fixed a scope level issue and did a more thorough tuning of my brake. I pretty much got the vertical dispersion down to about 1 1/4 MOA at 100 and 2 MOA at 200. It was a bit windy today, so don’t mind the windage variation.

First I did a gross tune of the brake, and then narrowed down to a small range.

The big problem is that I had the elevation pretty solidly on point at 100, but when I went to do a confirmation group, everything was suddenly .4 mil low. No f***ing clue why. I made zero adjustments. I had gone down range to add an additional target sticker, and it’s almost like someone adjusted my scope while I was down range.

I know this upper can occasionally do good groups, but I have zero confidence in its repeatability.

View attachment 665705
View attachment 665706

This “1.9” (labeled for the elevation used at 100) group below was shot right after all 12 of the 1.5” yellow targets above, with no adjustment made to the scope. WTF? I had parallax set properly and my holds were within the 1” yellow target.

View attachment 665708

200 seemed okay. Better than before.
View attachment 665709

what ammo are you shooting? try those norma tacs i told you about.

 

[PappyM3]

what ammo are you shooting? try those norma tacs i told you about.

Lapua Center-X. So I don’t think the issue is the ammo. And they performed the best out of the ammo I have on hand. I do have some SK Match Rifle coming in to try. But I’m going to run what I got with the Center-Xes at Granby this Sunday.

I’m perfectly happy with 1.25 MOA at 100. That I saw today. I just need to figure out why groups seemingly dropped 0.2 mil without any adjustment. The barrel may have cooled slightly, but it doesn’t explain all 20 shots being repeatably lower than the previous 65 shots.

It could be a fluke and the setup is just a 2 MOA setup at 100 yards.

I’ll keep an eye out for Norma Tacs.

I will also probably pick up a CZ 457 at some point and convert this upper to a 223 wylde 16” SPR upper, unless I can figure out these irregularities. Next thing to look at is looking at the muzzle brake and maybe putting on a target crown

 

[paul73]

I will also probably pick up a CZ 457 at some point and convert this upper to a 223 wylde 16” SPR upper, unless I can figure out these irregularities. Next thing to look at is looking at the muzzle brake and maybe putting on a target crown

i would keep it as is for 50yds drills and shooting off hand, as it is just fine for that distance.
a cz will be great for longer ranges. mtr varmint, wood or chassis. i like wood one better.

 

[PappyM3]

i would keep it as is for 50yds drills and shooting off hand, as it is just fine for that distance.
a cz will be great for longer ranges. mtr varmint, wood or chassis. i like wood one better.

Very well maybe. If (when?) I do a 457 down the line, I’m looking at the Grey Birch chassis. LaChassis-457 (Folding Stock/Long Forend)

I love the look of wood stocks, but a folding stock is too functional to ignore for taking backpacking.

But I did finally get some consistency. It looks like this rifle is just a 1-1.5 MOA rifle with Center-X.

Confirmed groups at 100: 1.14 MOA and 1.54 MOA
200: 1.39 MOA

I can live with that.

I was able to tune the rifle by … ditching the tuner brake.

 

[paul73]

Very well maybe. If (when?) I do a 457 down the line, I’m looking at the Grey Birch chassis.

That chassis is very nice. Check cz own models shipped in chassis also, it may be more price effective.

I was able to tune the rifle by … ditching the tuner brake.

I kept my mouth shut, but suspected as much, as I get best accuracy from all of mine 22lr with a thread protector only on a barrel.
Better/best ammo will improve grouping , but I reject an idea of paying 20c+ for a top tier 22lr rounds like SK rifle match.

Norma tac22 is out there now for $4.60 a pack that is also high, I get it at $3.70 or so, it pops up from time to time. Should be around 7cpr.

 

[PappyM3]

…
I kept my mouth shut, but suspected as much, as I get best accuracy from all of mine 22lr with a thread protector only on a barrel.
…

It is my first time trying a tuner brake, and I suspected it too. Finally decided to remove it and checked inside. It has a construction almost immediately in front of the muzzle, but with enough of a gap to cause some turbulence.

 

[mac1911]

22lr at 100/200 yards NO WIND most decent ammo at that 13 cent plus area SK plus, Center X , different Eley options , ---some guns like some ammo better BUT for the most part CCI SV if its a good lot will hover around moa out of anything I own with a good barrel IF I do my part

With my 513t/scoped thats now 80 years old will get around moa at 100 yards with Tennex
Kidd barrel and triggered, scoped 10/22 same will get close with CCI SV but I will say this not all CCI SV does well. I bought 2000 rounds of current production and this lot has its share of flyers
Tactical solutions 22lr upper is a bit looser over all but seems to like the current batch of SK plus I have been using and its seldom in no wind to get more than 1.5" groups at 100.

Out to 200 all three can hold the 10 ring of a SR target ( 3 moa) If I do my part and hold them, no wind

Now with the match sights--- im 3 to 4 moa shooter prone with a sling.

Toss in the wind .......shoot CCI SV

The best advice I have is if you buy 22lr that your rifle likes buy as much as the same lot # you can get!

My rascal with match sights does well also...

 

[PatMcD]

Nice , looking forward to a review

I forgot about this thread.
I shot in my indoor smallbore league last night after a covid hiatus of a couple-three years. Somebody talked me into using my Compass Lake upper with a SR-legal 4.5x scope instead of my usual Anschutz 54 with a 20x scope. I didn't really have high expectations, but gave it a go.
A couple of years ago when I was in pretty good smallbore form, I would usually clean the A17 prone target, but not always. Sometimes a 99, once in a while a 98.

Last night, I got a quick zero on my scope (because I'd never shot it at 50'), laid down and shot a 99 with a called bad shot. I call that pretty damn good accuracy, especially when I couldn't really see my shot placements because I never needed to bring a spotting scope before. I will next week.

So, to make a long story short, I'd say the accuracy is on par with my old Anschutz. Maybe not Olympic-class, but definitely enough to win a local match up against German rifles.

 

[paul73]

I forgot about this thread.
I shot in my indoor smallbore league last night after a covid hiatus of a couple-three years. Somebody talked me into using my Compass Lake upper with a SR-legal 4.5x scope instead of my usual Anschutz 54 with a 20x scope. I didn't really have high expectations, but gave it a go.
A couple of years ago when I was in pretty good smallbore form, I would usually clean the A17 prone target, but not always. Sometimes a 99, once in a while a 98.

Last night, I got a quick zero on my scope (because I'd never shot it at 50'), laid down and shot a 99 with a called bad shot. I call that pretty damn good accuracy, especially when I couldn't really see my shot placements because I never needed to bring a spotting scope before. I will next week.

So, to make a long story short, I'd say the accuracy is on par with my old Anschutz. Maybe not Olympic-class, but definitely enough to win a local match up against German rifles.

was it this one?

.22 Dedicated Match Rifle Upper on A4 receiver

Barrel Type Douglas Caliber .22 Twist 1-16

compasslake.com

 

[PatMcD]

was it this one?

.22 Dedicated Match Rifle Upper on A4 receiver

Barrel Type Douglas Caliber .22 Twist 1-16

compasslake.com

To tell you the truth, I don't know. I bought it as a kit, secondhand, from a guy who bought it originally. Probably the same barrel and 22 bolt as that upper you linked, but all other parts were mine.

I just went on the CLE website and it appears they do not offer the kits at this time.

 

[mac1911]

I forgot about this thread.
I shot in my indoor smallbore league last night after a covid hiatus of a couple-three years. Somebody talked me into using my Compass Lake upper with a SR-legal 4.5x scope instead of my usual Anschutz 54 with a 20x scope. I didn't really have high expectations, but gave it a go.
A couple of years ago when I was in pretty good smallbore form, I would usually clean the A17 prone target, but not always. Sometimes a 99, once in a while a 98.

Last night, I got a quick zero on my scope (because I'd never shot it at 50'), laid down and shot a 99 with a called bad shot. I call that pretty damn good accuracy, especially when I couldn't really see my shot placements because I never needed to bring a spotting scope before. I will next week.

So, to make a long story short, I'd say the accuracy is on par with my old Anschutz. Maybe not Olympic-class, but definitely enough to win a local match up against German rifles.

I always wanted a CL 22lr service rifle upper. My friend bought one for his son and it shoots very well.

 

[northny]

Very well maybe. If (when?) I do a 457 down the line, I’m looking at the Grey Birch chassis. LaChassis-457 (Folding Stock/Long Forend)

I love the look of wood stocks, but a folding stock is too functional to ignore for taking backpacking.

But I did finally get some consistency. It looks like this rifle is just a 1-1.5 MOA rifle with Center-X.

Confirmed groups at 100: 1.14 MOA and 1.54 MOA
200: 1.39 MOA

I can live with that.

I was able to tune the rifle by … ditching the tuner brake.
View attachment 665893
View attachment 665901
View attachment 665902

Congrats on a nice build. I like the look of the Ballistic X app, I’ll have to look into it.

 

[Taipan01]

I have the uncanny ability to buy firearms that become oddities. Either through short runs, companies changing hands (think Cerebus's run on buying everything in sight), simply put on hold due to public interest in other products never to be seen again, etc.. During the time of your choices being ABC and sometimes R, Bushmaster was pretty innovative on thinking out of the box and came out with things that others didn't do. One item they did but turned into a flash in the pan was to produce .22 uppers. First a carbine model and then an even a shorter run of rifle length (which I missed out on). It's the most accurate .22 I have of which I own a good number of.

All these Bushmasters are freaks in their own right but the .22 upper half was produced when everyone else was using cinnier(sp?) kits about 20 years ago.