Thank you Form I’m now a mk12 believer

[Remington92]

I’ve had the itch for a mk12 for a while and after reading another thread with form’s recommendation of a mk12 mod 0 I decided to take the plunge and pick up a pri upper.

Well I just got back from the range with it and all I can say is wow I’m impressed! I packed a few cheap 55gr to get on paper and then black hills 77 tmk, aac 77 smk, and aac tmk. All shot to basically the same poa. I didn’t do any break in just initial lube and ran the trigger bout as fast as I could get settled for next shot.

Only gripe I do have with this rifle is the ops inc brake is LOUD. My OCM5 needs to get out of jail soon. And if it shrinks the groups as much as I’ve heard they do on these rifles it may well be in top 3 most accurate rifles I own.

If you’re on the fence about one of these uppers just do it.


Black hills


Aac tmk over aac smk

 

[elkguide]

Looks like it has real potential!
Very nice.

 

[Formidilosus]

I’ve had the itch for a mk12 for a while and after reading another thread with form’s recommendation of a mk12 mod 0 I decided to take the plunge and pick up a pri upper.

Well I just got back from the range with it and all I can say is wow I’m impressed! I packed a few cheap 55gr to get on paper and then black hills 77 tmk, aac 77 smk, and aac tmk. All shot to basically the same poa. I didn’t do any break in just initial lube and ran the trigger bout as fast as I could get settled for next shot.

Only gripe I do have with this rifle is the ops inc brake is LOUD. My OCM5 needs to get out of jail soon. And if it shrinks the groups as much as I’ve heard they do on these rifles it may well be in top 3 most accurate rifles I own.

If you’re on the fence about one of these uppers just do it.

View attachment 757466
Black hills
View attachment 757461

Aac tmk over aac smk
View attachment 757462

Good to see. They really are more than the sum of their parts.

 

[Nightstandx]

grate result from a beautiful built rifle. congrats

 

[sierracharlie338]

Love me a good MK12 and PRI makes a good one!

 

[gbflyer]

You guys are real expensive to read.

 

[ramblinman]

I’ve had the itch for a mk12 for a while and after reading another thread with form’s recommendation of a mk12 mod 0 I decided to take the plunge and pick up a pri upper.

Well I just got back from the range with it and all I can say is wow I’m impressed! I packed a few cheap 55gr to get on paper and then black hills 77 tmk, aac 77 smk, and aac tmk. All shot to basically the same poa. I didn’t do any break in just initial lube and ran the trigger bout as fast as I could get settled for next shot.

Only gripe I do have with this rifle is the ops inc brake is LOUD. My OCM5 needs to get out of jail soon. And if it shrinks the groups as much as I’ve heard they do on these rifles it may well be in top 3 most accurate rifles I own.

If you’re on the fence about one of these uppers just do it.

View attachment 757466
Black hills
View attachment 757461

Aac tmk over aac smk
View attachment 757462

Can you do me a massive favor.

Shoot two groups back to back and change pressures into the gun. Say one pretty heavy into the bipod and one pretty slack

I seen a pretty massive shift in impact with most of my traditional style free float hand guards (urx4, mk16, mk8, bcm qrf, etc etc) The worst was a few years back with a KAC ras hand guard on a mod 1 build. Always attributed it to operator error or slow lock time. Groups are tight, but across the board you can influence group shift fairly easily. Off the sandbags on a bench she’s tidy, but in the field 2moa is hard to hold.

Ledzep a ballistician at hornady commented on the ‘hide about how his seekins (a semi monolithic hand guard) would exhibit a .5 mil shift vertically depending on shooting position. He was 2nd in the gas gun division of prs last year so it’s not “he can’t drive a gasser”

The mod 0 top rail might lock it all in tight enough to mitigate this phenomena.

Either way sweet looking rifle. Love a mod 0, makes me want to sell off my KAC ras mock 1 and built a mod 0

 

[Formidilosus]

Can you do me a massive favor.

Shoot two groups back to back and change pressures into the gun. Say one pretty heavy into the bipod and one pretty slack

I seen a pretty massive shift in impact with most of my traditional style free float hand guards (urx4, mk16, mk8, bcm qrf, etc etc) The worst was a few years back with a KAC ras hand guard on a mod 1 build. Always attributed it to operator error or slow lock time. Groups are tight, but across the board you can influence group shift fairly easily. Off the sandbags on a bench she’s tidy, but in the field 2moa is hard to hold.

Ledzep a ballistician at hornady commented on the ‘hide about how his seekins (a semi monolithic hand guard) would exhibit a .5 mil shift vertically depending on shooting position. He was 2nd in the gas gun division of prs last year so it’s not “he can’t drive a gasser”

The mod 0 top rail might lock it all in tight enough to mitigate this phenomena.

Either way sweet looking rifle. Love a mod 0, makes me want to sell off my KAC ras mock 1 and built a mod 0

POI shift due forend/barrel nut shift is real. MK12 Mod 0’s are far less effected than most setups.

 

[orangetractor]

Beautiful rifle, would love to get PRI upper one of these days when the economy gets better. I thought I read Allen Engineering quit making suppressors due to maybe owner retiring or something along those lines.

 

[Fireflyfishing]

This is an SBR?

 

[orangetractor]

No, it’s an SPR. Mod 0 should measure 18”.

 

[gbflyer]

Is the A1/A2 buttstock the way to go?

 

[orangetractor]

Is the A1/A2 buttstock the way to go?

My opinion/experience, go A2. I’ve had a lower with A2 buttstock for years and enjoy it. I decided to put A1 stock on a lower that I put together for a 300blk hog/whitetail rifle, thinking it would shoulder better with thick jacket/coat on…I was wrong. Now I’m looking for another quality A2 buttstock to replace it with.

 

[ramblinman]

Yeah the a1 isn’t as good as the a2 for my use if going prone is a regular thing.

 

[NSI]

My opinion/experience, go A2. I’ve had a lower with A2 buttstock for years and enjoy it. I decided to put A1 stock on a lower that I put together for a 300blk hog/whitetail rifle, thinking it would shoulder better with thick jacket/coat on…I was wrong. Now I’m looking for another quality A2 buttstock to replace it with.

I’ve got a black one you can have.

-J

 

[Remington92]

Anyone have pet load recommendations for 77tmk at ar mag length with powders that are available? Reading it sounds like most recommend
xbr- unobtanium
tac- sounds very temp sensitive but cheap and available
leverevolution- temp sensitive but semi available
2520- semi available and temp sensitive
h4895- worse availability than xbr
Varget- available but cant fit enough in case to get any kind of speed
staball match- available but sounds like a flop
need to do more reading on the vihtavuori options

 

[wind gypsy]

Anyone have pet load recommendations for 77tmk at ar mag length with powders that are available? Reading it sounds like most recommend
xbr- unobtanium
tac- sounds very temp sensitive but cheap and available
leverevolution- temp sensitive but semi available
2520- semi available and temp sensitive
h4895- worse availability than xbr
Varget- available but cant fit enough in case to get any kind of speed
staball match- available but sounds like a flop
need to do more reading on the vihtavuori options

Benchmark.

 

[Dave Thomas]

Xbr has been coming around lately but only in 1 pounders.

 

[WestTN2288]

Anyone have pet load recommendations for 77tmk at ar mag length with powders that are available? Reading it sounds like most recommend
xbr- unobtanium
tac- sounds very temp sensitive but cheap and available
leverevolution- temp sensitive but semi available
2520- semi available and temp sensitive
h4895- worse availability than xbr
Varget- available but cant fit enough in case to get any kind of speed
staball match- available but sounds like a flop
need to do more reading on the vihtavuori options

25-26gr of lever has been hard to beat for accuracy, velocity and price

 

[Clark33]

I have a PRI Mod H (16" barrel) AEM5 suppressor, chrono'd the 75gr hornady black. Accuracy was good, but that stuff seems a little dirtier than some other stuff I've tried.