MK 12 Picture & Discussion Thread

My recent builds including a large frame inspired by the MK12. And yes, I know the MK12 is missing something... My first SPR barrel was awful, 2-4 MOA was the norm so I swapped it out and need to install the collar and brake yet. Cans for both are at the dealer waiting for me to get off my ass and drive over to get them.
 

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Looking for opinions/recomendations. I’m putting together an early MK12 Mod 0 and have 2 options for optics. One is a pre mark 4 Vari-x iii 3.5-10x40 (non illuminated) and the other is a Mark 4, m-3 10x40 lr/t with mil dot. What do you guys think?
 
Looking for opinions/recomendations. I’m putting together an early MK12 Mod 0 and have 2 options for optics. One is a pre mark 4 Vari-x iii 3.5-10x40 (non illuminated) and the other is a Mark 4, m-3 10x40 lr/t with mil dot. What do you guys think?
I had a mk4 2-8 and currently have a vari-x iii illuminated. The vari-x to me is more clear and honestly a really nice scope. I'd put it against a lot of today's offerings. Just my opinion/experience.
 
Looking for opinions/recomendations. I’m putting together an early MK12 Mod 0 and have 2 options for optics. One is a pre mark 4 Vari-x iii 3.5-10x40 (non illuminated) and the other is a Mark 4, m-3 10x40 lr/t with mil dot. What do you guys think?

I ran the VariX III 3.5-10 M3 for years. It’s a wonderful scope. Only reason I moved it off is I like the fixed parallax of the NXS Compacts better for speed shooting.
 
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Looking for opinions/recomendations. I’m putting together an early MK12 Mod 0 and have 2 options for optics. One is a pre mark 4 Vari-x iii 3.5-10x40 (non illuminated) and the other is a Mark 4, m-3 10x40 lr/t with mil dot. What do you guys think?
both sound like reasonable options. Do you have both?
 
Suppose it's time to post my rifle I finished about a week or so.

Lower
H&r m16a1 lower in black.
Ssa-e trigger
Ergo grip
Schmid ambi selector
Brownells 20 round mags

Upper
Colt upper
Douglas 18" barrel
New kac mk12 rail
Kac bipod mount
Kac sling swivel
Long collar mk 12 w/ mk 12 muzzle device
Kac black frint sights
Kac micro rear sight
Gasbuster mil latch
Nightforce nx8 2.5-20 on a condition 1 mount.
Tas-1 sling
Manual and cartridge book
Pelican 1700 w/ cut foam by cobra.
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Took my Son In Laws ModH out yesterday. I pulled the 2.5-10x24 NXS as it has some binding in the mag adjustment and it’ll need to go back for service. In the meantime, put a NX81-8 with FC-DMC in a Reptillia mount. Looks crazy out of place but it’s a nice unit so far.

Got a rough zero at 100 and then shot one group to see if the load was working in this rifle.

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.91 outside to outside, a hair under .7 center to center. Not bad with an 8x fixed parallax off a Harris and a shmedium out back . Confirmed come ups to 600 yards.

Looks like this load is a touch faster than 2600. About 5 MILs to 600. A little wind and it was 95 with humidity, but for less than 75 rounds down the tube I’m happy with this rifle.

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This will probably wear a Mk5 HD 3-18 when he gets it.

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Got the lpk all installed. Went with a h&r m16a1 lpk since it was near impossible to find an A1 grip in stock separately. Trigger is geissele SSA-E. Popped on the mid rings also.

Need a new sopmod stock, I painted the one I have and krylon is not coming off as cleanly as I hoped. Also need a gasbuster. I bought a fde one because I'm stupid.

Was going to make my own barrel but I'm really tempted to just push the way button and get a Douglas. The last one I had on my mods was no joke 1/3-1/2moa with 77 handloads.

My silencer guy also just happened to have an old NOS aem5 from when Ron made them. Said he bought it for himself and just never built the gun and let it go for me. Been waiting about 1.5 months so far on a trust 🤞

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Got the lpk all installed. Went with a h&r m16a1 lpk since it was near impossible to find an A1 grip in stock separately. Trigger is geissele SSA-E. Popped on the mid rings also.

Need a new sopmod stock, I painted the one I have and krylon is not coming off as cleanly as I hoped. Also need a gasbuster. I bought a fde one because I'm stupid.

Was going to make my own barrel but I'm really tempted to just push the way button and get a Douglas. The last one I had on my mods was no joke 1/3-1/2moa with 77 handloads.

My silencer guy also just happened to have an old NOS aem5 from when Ron made them. Said he bought it for himself and just never built the gun and let it go for me. Been waiting about 1.5 months so far on a trust 🤞

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What am I seeing behind the 9 o’clock pic rail up front? Black, half moon shaped?
 


Thought this video was enjoyable to watch. Most of it known info. Just cool to see them all lined up. Makes me really regret selling my mod 1. And want to kick start a 22 arc Mod 0 or 1.


I watched this last night. There has been so much mk12 content put out over the last 10 years it’s hard to sift through what is legit info and what “loose” history.

I enjoyed the show, and it’s going to be even harder to decide if my next will be a Mod1 or a RECCE. After shooting the ModH side by side with the Mod0, I may take the MV hit. Might even get fucking crazy and go with an AEM2/4 to keep the form factor and further shorten it. Even if I go AEM5 it would have at least a mid-length, if not intermediate gas system because why not? As long as the gas block is hidden, fuck it. (Triggering cloners before 7AM ;) )
 
Got the lpk all installed. Went with a h&r m16a1 lpk since it was near impossible to find an A1 grip in stock separately. Trigger is geissele SSA-E. Popped on the mid rings also.

Need a new sopmod stock, I painted the one I have and krylon is not coming off as cleanly as I hoped. Also need a gasbuster. I bought a fde one because I'm stupid.

Was going to make my own barrel but I'm really tempted to just push the way button and get a Douglas. The last one I had on my mods was no joke 1/3-1/2moa with 77 handloads.

My silencer guy also just happened to have an old NOS aem5 from when Ron made them. Said he bought it for himself and just never built the gun and let it go for me. Been waiting about 1.5 months so far on a trust 🤞

View attachment 8480320

Is that a PRI sleeve? or the swan?
 
Used to, haven't been there in a few years now. Let my membership lapse like a dumbass when I decided to get outta shooting for a while 🤦🏻‍♂️ May have to see about rejoining if there isn't a huge wait list.
I'm not sure there is one but he keeps mentioning having to close off membership soon. He's expanding and changing some things around. Getting an archery area and opend up a big 5 stand clay station.
 
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Welp got the atf approval today for my AEM can. Only 1.5 months (submitted mid july) on a trust so I'm way ahead of where I thought I'd be. I decided since it cleared so quick and I have yet to build my barrel I bit the bullet and ordered a Douglas barrel from pri with a 1/8 twist and a proper gas buster. Also picked up a sopmod stock for about $65 while sales are going on.

Figure 2 weeks I'll have my first shots on this "proper" mod 0!
 
Welp got the atf approval today for my AEM can. Only 1.5 months (submitted mid july) on a trust so I'm way ahead of where I thought I'd be. I decided since it cleared so quick and I have yet to build my barrel I bit the bullet and ordered a Douglas barrel from pri with a 1/8 twist and a proper gas buster. Also picked up a sopmod stock for about $65 while sales are going on.

Figure 2 weeks I'll have my first shots on this "proper" mod 0!
Why the 1/8 twist?

Be sure to get pictures up.

My WOA SPR barrel stil has not been delivered. It is the last part for my build.
 
Why the 1/8 twist?

Be sure to get pictures up.

My WOA SPR barrel stil has not been delivered. It is the last part for my build.
Because by the time I got off my ass the 1/7 black was sold out 🤣. AMU uses 1/8 and there should be no discernable accuracy difference in the range the spr is capable of. Some reports that the 1/8 is more accurate to 600 which is why the AMU uses it on those guns. Supposedly the 1/7 was specified so it can handle tracer rounds.... overall I have no clue but I don't believe there will be a performance difference.
 
Because by the time I got off my ass the 1/7 black was sold out 🤣. AMU uses 1/8 and there should be no discernable accuracy difference in the range the spr is capable of. Some reports that the 1/8 is more accurate to 600 which is why the AMU uses it on those guns. Supposedly the 1/7 was specified so it can handle tracer rounds.... overall I have no clue but I don't believe there will be a performance difference.
As 77 grain match ammo is pretty hard to get here, i have limited experience.
My go to has been Normas 69 grain GTX and they seem to work fine in either 1/7 and 1/8 twist.

I did order a 1/7 though.
 
I'm still debating of I need a mk12 mod 0 since I have my mod 1 now. I keep looking at them and keep wanting one, but I have enough 5.56 rifles with my block 1, block 2, ris iii build almost identical to my block ii, mk12 mod 1, and a sig 556 swat.

That being said, I built my mod 1 piece by piece. With the mod 0 I am debating to do a piece by piece build, buy an upper from pri and get an h&r lower then cerakote it to match, or a full rifle purchase.
 
Because by the time I got off my ass the 1/7 black was sold out 🤣. AMU uses 1/8 and there should be no discernable accuracy difference in the range the spr is capable of. Some reports that the 1/8 is more accurate to 600 which is why the AMU uses it on those guns. Supposedly the 1/7 was specified so it can handle tracer rounds.... overall I have no clue but I don't believe there will be a performance difference.

Not sure this is accurate but I know does .@sinister
 
With a bit of luck, it looks like my WOA barrel will finally make it to my hands this week. Some shit is just horrible to get your hands on here, while other stuff is just a matter of click and collect.
Come thursday, I have been wating 10 weeks to get the barrel. But on the other hand it took all of 3 days to get my Ops Inc style suppressor from the Acheron dealer. So there is that.
 
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USAMU used/made both during my time there (a while ago). Depends on what blanks were in the supply room.

Proof is in the performance. Every single USAMU build gets tested -- there's no wondering whether or not the build was right.

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And I defer to you 😘. But sounds like 1/8 or 1/7 could be capable as long as the blank was a good one.

If 1/8 sucks I'll just sell finish my own barrel or get a 1/7 when it comes in stock.
 
And I defer to you 😘. But sounds like 1/8 or 1/7 could be capable as long as the blank was a good one.

If 1/8 sucks I'll just sell finish my own barrel or get a 1/7 when it comes in stock.

I shot 1:8 for years with 69s, the original Nosler 75s and the 80gr SMK and it shot great. Didn’t mean to imply the twist was an issue, just that I don’t know if AMU used it. Last time I shot next to them, they were running 6.5 or 6 twists with 90gr JLKs. I was policing Walter’s brass on the line at ORSAs while we were chatting and he advised that shit never be used again ;)
 
For DMRs and SPRs we don't shoot 80s for slow-fire.

The majority of the ammo through DMRs will be M855A1. Through SPRs mostly 77s. Really depends on the customer and training audience.

I think my last personal SPR barrels have been Satern Liberty, Roscoe, and White Oak.

Wannabe SPR. Needs rattle-can:

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Could have been assembled tonight but I was an idiot. Left my gas block, bcg, brake/collar at my parents thinking I wasn't going to buy a barrel. Left it there knowing I needed it to make my barrel so I wouldn't forget it.

Anyway, Douglas came in, gasbuster and socom stock. Should have her together and mated with her suppressor in 2 weeks.

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So this is it. The all out build.
It now has a WOA SPR 18" barrel, 1/7 twist. I know, mod H should have a 16" but I cant have one do to legislation.
The suppressor is the European version of the legendary Ops Inc AEM5. Made by Acheron and it is pretty damn amazing. Much more quiet than the flowthrough suppressor I had before, but as you can imagine, also a lot gassier than the flowthrough suppressor was.
I only ran 44 rounds through it today. Best group was 5 shot @ 100 meters, mearsuring 27mm C/C. I am sure it will only get better.
 
Ok! So back from another range trip.
Wanted to set a good zero with the matchammo I have the most of, which is Normas GTX 69 grain.
After some minor adjustments I collected a 20 round "group" from prone, it is really 2 5-shot groups and 1 10-shot group all shot at the same target from 100 meters, it measuers 67mm C/C (2.63").
I know, its weird and not really ideal as I broke position between each string of fire. But my POA and POI was pretty much spot on, and repeatable. And the barrel should have a few hundred rounds through it before its time to really try shooting bug holes anyways.
 
After some minor adjustments I collected a 20 round "group" from prone, it is really 2 5-shot groups and 1 10-shot group all shot at the same target from 100 meters, it measuers 67mm C/C (2.63").
Two things, I usually try several readily available loads out of my rifles just to see if it something works better. I use the ballistic software but I normally look at aggregates, so I start to feel good about the accuracy of a rifle after two or three range trips and 75 to 100 rounds fired.
 
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24.4gr if either Varget or RL15 are wonderful loads with 77s. A touch slow at maybe 2650-2675, but very accurate and consistent. I like 7 1/2 BRs and 450Ms. (Or old Russian magnums if you can spare them) You can play with a taper crimp and primers to really tune it in, it I’m not good enough to realize the difference so I just load and shoot.

AR Comp caught me off guard. I’m sure it’ll get you massive MV, just be careful. I dropped 20 of 20 primers into my trigger :) I know several guys who love it for Palma loads with 155s, But at todays prices for AR Comp I’m sticking with Varget.
 
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