So, today I built another Mk12MOD1......sorta

[blcouch]

I've had this project in mind since I put my original MOD1 together in 2005. I never really liked the options I knew about so I shelved the idea. I did have a spare brake and collar new in wrap and a flat top upper so I had a start.

Fast forward to earlier this year and Boltcarrier had the stripped KAC lowers. I picked one up with a vague notion that I'd do a Mk12, a Mk18, a .300 blk or what I built today. A FFRAS came up on arfcom for a decent price, and two months ago I caught wind that Compass Lake Engineering would do a Mk12 profiled .22 rimfire barrel and VOILA!

I have a set of ARMS 22 rings arriving in the morning and a Leupold Mk4 2.5-8x36 coming Saturday. Pics will follow. The Krylon and Rustoleum texture coat paint job will probably have to wait until next time I'm home. So will accuracy testing.

I got most of my smalls from Brownells. A vise and receiver hitch mounting plate from Harbor Freight, a torque wrench from AutoZone and a vise block from Midway wrapped up the tools needed. I used a stock trigger for now and went with a B5 stock kit. I did use a Sierra Precision grip as on my 'real' MOD1. This being my first complete ( putting barrel on, torquing it, etc) it went almost flawlessly. I didn't lose any springs, detents or anything. I did have to cut a small section of a finish nail to put in the grip hole for the selector lever spring because it was too deep to apply good pressure on the detent. The upper receiver insert for the vise block wasn't made for a rimfire barrel so I had to Dremel the ejection port cover detent notch bigger to allow everything to fit together while in the vise. I'll post pics of my vise setup and block mod tomorrow. Any questions, shoot.


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[blcouch]

Painted my go-to style and with scope and rings. Scope is MR/T 2.5-8 and rings are ARMS 22 medium. They give great eye relief for the .22 non-recoil

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[deltawiskey]

That rifle turned out awesome!
Thank you for posting it
DW

 

[FUNCTIONAL]

I really want to see how she shoots lol.

 

[woogie_man]

Agreed...waiting on a range report.

Looks great otherwise though.

 

[blcouch]

Range report will be delayed 22 days or so. Out for another 20 day hitch so I'm looking at July 11 at the earliest. I'm gonna shoot it head to head with my 40xb in the McM A1 stock. Same ammo, same distance, same sitting. That will be interesting to see. If I decide on a better trigger for the Mk12.22 I'll get one otherwise I'll do the cut and bend trick I saw on Arfcom a decade or so ago. It worked well on 2 rifles so far so I don't see why it won't work on a .22. We shall see.


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[FUNCTIONAL]

Mk12.22

i feel your pain on working away from home. Looking forward to you getting done time with it. Always loved my mk12 and having a 22lr version would be just as cool.

 

[NukeMMC]

I have been thinking about having Frank do a MK12 Mod 1.22 upper for me also. My MK12 Mod 1 has a NF 2.5-10x24 in NF high rings, so may do a 2.5-10x32 on the .22.

Any thoughts about running the RF ammo thru the 12th Model?

 

[blcouch]

I have been thinking about having Frank do a MK12 Mod 1.22 upper for me also. My MK12 Mod 1 has a NF 2.5-10x24 in NF high rings, so may do a 2.5-10x32 on the .22.

Any thoughts about running the RF ammo thru the 12th Model?

I used Frank's barrel and bolt kit and rolled my own. I figured it was time I bought the tools and did it from the ground up.

The 12th and rimfire: Waaaaaay back in 2004-5 SteveO from ADCO made comments to the effect that rimfire would be fine as long as you ran 5.56 through it intermittently to clean it out(he even had a Ruger 22/45 set up for one, for grins I guess). Ron Allen/K31user on Arfcom backed up that statement(s) as far as I can remember. I've used my 12th on a CZ452 Varmint set up with the brake/collar since 2008 with no ill effects. YMMV. I'm seriously considering my next can be an AEM5 just for this .22LR Mk12 so there won't be a constant moving of the 12th from case to case. I'd like each 'system' to have it's can in the same bed, so to speak . Thankfully I don't have the 'get one can to use on everything I have' syndrome, but I do tend to get one can for 2 platforms if I have the desire for two of the same caliber. I have a 7.62 can for my 2 7.62s, a 9mm can for my two non-MPX pistols, a .22 can for my 2 .22 pistols and a pending 5.7 can for my yet to get FiveSeven. The .22 can is the only serviceable unit I have but it's also the highest volume unit I have that would necessitate service.

Back on track: The 12th stays pretty clean between the 5.56 and brake cleaner. Again , YMMV.


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[Primus]

Very Neat. How much was the barrel if you don't mind me asking?

 

[blcouch]

Very Neat. How much was the barrel if you don't mind me asking?

Barrel and bolt/carrier was $605. It is a Mk12 profile. Included 2 M261 10 round inserts and a load enhancing tool for single loading.


Edit to add: Douglass barrel 1-16 twist


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[jLorenzo]

That's really cool. What reticle is in that leupold? Definitely interested in seeing how it shoots.

 

[blcouch]

That's really cool. What reticle is in that leupold? Definitely interested in seeing how it shoots.

Reticle is the TMR. Initial testing indicated the potential for superb accuracy. When one of my mild steel 3/8" plates turned sideways on the wire it hangs on, I was able to hit it on edge a few times to get it to turn. At 92 yards. In 12 days I'll be able to test it properly at varying ranges.


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[nakas]

Nice to see another dedicated 22lr Mk12 mod1 out there! Here's my Compass Lake before and after.

 

[blcouch]

Nice to see another dedicated 22lr Mk12 mod1 out there! Here's my Compass Lake before and after.

Very nice. I see you went with all 261 mag inserts. I have the 2 my kit came with but ordered 6 Blackdog Machine 25 round mags for more trigger time and less loading per session, plus my 5.56 mags are all loaded and I have a 500 rd case of Mk262 coming : D. One thing: I couldn't get the 261 inserts to work with 20 round mags. Do they only work with 30s or maybe I didn't try hard enough?


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[nakas]

They're suppose to work with either a 30 or 20. I haven't had any issues.

 

[blcouch]

25 yd ammo test. Top right is 5 from a clean cold barrel. Top left is second 5. Bottom left is third 5. Bottom right is fourth group, but 10 rounds. Center group is fifth with 5. Center low is sixth group of 11. The first five groups are CCI standard velocity 40 gr at 1070 fps. The center low group is Aguila Sniper Subsonic 60 gr. The 40 gr and 60 gr have the same POIA/POI at 25 yds. I have some other ammo to test but time ran short this time in the rear. Second week of August will bring round 2 of testing and various ranges. I should be able to test to about 125-130 yds on my backyard range.

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