MK12 Mod Wormydog

[Wormydog1724]

In my quest for AR Supremacy, I have found my safe full of SBR's. Nothing wrong with that but I have decided to try something different. I have recently been turned on to the MK12 Mod 0. I like the style, look, feel, and utility of it.

Already having two AAC cans, I really don't want to spring the cash for the correct OPS can. I am going to make do with what I have. I do not want to use an 18" because with my can it will leave a lot of barrel exposed. Nothing wrong with that, but its my build and I want it a certain way. With my research I found there is a 16" midlength MK12, designated the MK12 Mod H for Holland. I don't know the history of it but have seen it around the interwebz. It uses the OPS can and the PRI gas block/front sight can't be used, not enough room for the rail and can and gb/fs.

I said to myself "Self, why don't you just make a MK12 dissipator?". And therefore I am.

Here's the plan, use a BCM SS410 16" Midlength barrel with lo pro gas block, PRI 12" Gen III handguard, PRI SPR PEQ top rail, then put the PRI gb/fs in front of the hand guard in the rifle spot. Obviously it will not be a functioning gas block, but a folding front sight. Hence making it a Dissipator, but a MK12 Mod H at the same time.... and there I have a MK12 H/D.

I know its a cluster **** of setups but I think it will work and look slick too.

Parts list:
BCM 16" SS410 midlength barrel
BCM low pro gas block and gas tube
Probably BCM BCG
PRI 12" Gen III handguard black
PRI SPR PEQ full length top rail
PRI gas block/front sight
PRI gs buster CH, just because I have one and its never getting used otherwise
ARMS #40 rear sight, probably low profile
ARMS #22 rings, probably medium since I'm using....
Trijicon Accupoint TR20 green mil-dot 3-9x40
unknown upper receiver I had laying around
Not sure on the lower or which stock I will go with, maybe SOPMOD, PRS, or A2
Geisselle SDE for the trigger because I already have that.
AAC SDN-6
AAC M4-2000 when the stamp arrives

Again its not an exact clone, not really a clone at all. More of a mutt of several configs rolled into one. Its not a she, it doesn't have a girls name. Its a gun, a firearm, a defensive weapon, a gosh damn ****ing boom stick.

Here's what I have so far.

http://i416.photobucket.com/albums/pp247/wormydog1724/2ACE30BC-A900-4B34-A821-755FD07DB5BE-7724-0000073F55952807_zps88d3f789.jpg
Not pictured is the SDN-6 which is on my MK18 right now

Since the barrel steps down from .750 at the gas block to .725, then again to .700 an inch behind the threads, I am going to have to modify the PRI gb/fs so it clamps securely to the .725. I don't think it will be big deal though.

http://i416.photobucket.com/albums/pp247/wormydog1724/CB6562D0-EEC1-4338-BC57-A7E890997FDB-5750-000005A0A3996EE4_zpsa1908b0b.jpg


Here's an artists rendering of it. The optic and suppressor will be different than pictured however.

http://i416.photobucket.com/albums/pp247/wormydog1724/myweapon_zps74d179bf.jpg

Question comments concerns?

[David Thomas]

Cool project. I love the mk12 mod 0.

Since it is not a clone, i would go a Vltor emod or imod. There are a lot of stock choices, but those are my favorites.

[themissinglink]

I like it.

[Wormydog1724]

I apologize to Iraqgunz for not posting a complete build. I am going to keep updating this thread as the parts come in and as I assemble it. And of coarse a finished firearm and range report. Please don't lock my thread. :cool:


ETA: holy shit when did I become a 'senior member'? That's interesting. Is it just by post count?

[docsherm]

I think you will be OK as long as you stake the castle nut........lol. ;)



I like it. I will be standing by to see the complete build....have you thought of a UBR for the stock?

[Wormydog1724]

I think you will be OK as long as you stake the castle nut........lol. ;)



I like it. I will be standing by to see the complete build....have you thought of a UBR for the stock?

I have thought about the UBR, but when I have used it before on two previous builds, both of which were lighter than this particular one, it just seemed to make the entire weapon too heavy. No I'm not a puny pansy pantywaist. And I probably, no not probably, I won't be humping this weapon for long distances, but I don't want it just overly obese either. But you say, 'then why do the PRI top rail, and other non-essential parts that ultimately add weight?'. And I say, because. :D

Honestly though the UBR is being considered, but not real hard. I will say it did somewhat add balance to the guns I put it on before, but at the cost of adding too much overall weight, for me.

[Nka727]

Snow camo. Definitely snow camo.

[VIP3R 237]

Good looking build to be.

Is that the pimpmygun website?


I apologize to Iraqgunz for not posting a complete build. I am going to keep updating this thread as the parts come in and as I assemble it. And of coarse a finished firearm and range report. Please don't lock my thread. :cool:


ETA: holy shit when did I become a 'senior member'? That's interesting. Is it just by post count?

Yes the Senior mark is 1000 posts.

[Wormydog1724]

Good looking build to be.

Is that the pimpmygun website?



Yes it is. The version 2 has more better parts but version 1 has the pri handguard.

You do good hydro work. I had my 6.8 dipped by a company here in Okla. I thought about having this build dipped, but I'm not sure which pattern I would go with. My 6.8 has a mossy oak brush type pattern, it's by Outwest actually but looks like the mossy oak kinda.

[Wormydog1724]

Got a few more parts in the mail today.

http://i416.photobucket.com/albums/pp247/wormydog1724/fe901734-3a05-47e5-9e95-3bcc9c5a4dd2_zpse654dfd1.jpg

On the way are the ARMS #22-M, #22 TRC, #22 TRR, #37 RI, #40 LP.

Should be done afte those are installed, then I shoot it!

[rubber ducky]

I'm curious - how did you modify the clamped on fsb to securely attach to the reduced diameter portion of the barrel?

[docsherm]

That is looking real good. I can't wait for a range report.

[Walleye]

How much weight does that PRI SPR rail add? Does it affect the handling or balance much?

[Wormydog1724]

I'm curious - how did you modify the clamped on fsb to securely attach to the reduced diameter portion of the barrel?

Removed material between the clamps to make it clamp more.

[Wormydog1724]

How much weight does that PRI SPR rail add? Does it affect the handling or balance much?

It's negligible. The suppressor adds the most weight, then the bipod. This isn't meant for "running and gunning" so it doesn't bother me.

[rubber ducky]

Removed material between the clamps to make it clamp more.

Gotcha. Thanks!

[TahoeLT]

^Agreed, the Mod 0 isn't a run-and-gun kind of rifle. The Mod 1 is a lot handier for that kind of thing, which is why I had to build one after finishing my Mod 0...

That is looking pretty sweet, and a good modification to use an existing can. Have you hit the range yet?

[VIP3R 237]

Yes it is. The version 2 has more better parts but version 1 has the pri handguard.

You do good hydro work. I had my 6.8 dipped by a company here in Okla. I thought about having this build dipped, but I'm not sure which pattern I would go with. My 6.8 has a mossy oak brush type pattern, it's by Outwest actually but looks like the mossy oak kinda.

Yeah that site is a great way to pass the time.

Thanks, it's a lot of fun. One of the newer patterns that i really like besides the Kryptek patterns is the Orion Design Group Lupus camo. WTP-661 is the film number. It's kind of a mesh between multicam, brush, and digital.

[Wormydog1724]

Have you hit the range yet?

No I haven't. All of the parts are not here yet.

[Walleye]

It's negligible. The suppressor adds the most weight, then the bipod. This isn't meant for "running and gunning" so it doesn't bother me.

I have a similar setup but without the top rail, but I was thinking about getting one of the other PRI top rails if I could maintain my existing rail mounted front sight. When I ditch the scope and the bipod it feels fairly handy, but a top rail is more of a permanent solution than a QD bipod and scope.

[Salty Sourdough]

Sweet build! I've got a bcm ss410 16" I plan to do something similar with.

[SBJtactical]

lookin good!

[Wormydog1724]

Now just need some time behind the trigger.

http://i416.photobucket.com/albums/pp247/wormydog1724/10DC5208-1D6A-48C2-B1DF-4062560DDD9D-4452-00000560757294A1_zps7b4c1966.jpg

[themissinglink]

Looks awesome, PRI stuff is always sweet!

[Wormydog1724]

http://farm8.staticflickr.com/7362/9177965097_69c3bc517f_b.jpg (http://www.flickr.com/photos/94844416@N02/9177965097/)
mk12modhd2 (http://www.flickr.com/photos/94844416@N02/9177965097/) by wormydog1724 (http://www.flickr.com/people/94844416@N02/), on Flickr

http://farm4.staticflickr.com/3778/9177969749_d2a2b33ef6_b.jpg (http://www.flickr.com/photos/94844416@N02/9177969749/)
MK12MODHD (http://www.flickr.com/photos/94844416@N02/9177969749/) by wormydog1724 (http://www.flickr.com/people/94844416@N02/), on Flickr

[Salty Sourdough]

Awesome pics, that pri front sight just sets the whole thing off. Got any pics without the can, how does it shoot?

[docsherm]

How are you liking that scope? I love my AccPoints but I would prefer if it were a 30mm tube. What do you think?

[Wormydog1724]

Sorry its taken so long for me to get back to this thread. Been busy this summer and haven't been able to get out to shoot much. But last night I did load up some 40 grain V-Max bullets with some Varget powder. I did 26.2, 26.5, 27, and 27.2 grains, 10 rounds each. I got out today after work, 92 degrees and no wind. I shot the left group first each time, then the right group. I wasn't going as slow as I should have, but **** it was hot and I was ready to go home.

Anyways, I started with the lowest and watched for signs of pressure or whatever, and my last 10 rounds I put my can on and shot 10 more rounds of the 26.5.

Here are some pics

http://i416.photobucket.com/albums/pp247/wormydog1724/40grvmax262varget-1_zpsb73dcf04.jpg

http://i416.photobucket.com/albums/pp247/wormydog1724/40grvmax265varget-1_zpsaa729eae.jpg

http://i416.photobucket.com/albums/pp247/wormydog1724/40grvmax27varget-1_zpsc85bf1c5.jpg

http://i416.photobucket.com/albums/pp247/wormydog1724/40grvmax272varget-1_zps722d0e95.jpg

http://i416.photobucket.com/albums/pp247/wormydog1724/40grvmax265vargetsuppressed-1_zps9a1166d4.jpg



I'm going to try the 27 and 27.2 again with the can on and try to figure out exactly how much shift I am experiencing with and without the can.

I've got the Giesselle Super Dynamic Enhanced trigger in it. Not a bad trigger but not my favorite. Actually wanting to trade it for a different Giesselle trigger, any suggestions?

The 26.2 grains was definitely the most pleasant to shoot. Soft recoiling and not loud without the can. But of coarse the accuracy was the worst. The 27 and 27.2 had some pop to them, I don't think I will try more than 27.5 because the 27 and 27.2 were both slightly compressed. Not that that bothers me, but just don't want to tempt it. The oal was 2.255-ish, as long as I could go and still fit in the mag. Seemed to work pretty well. I am working up the 40 grains because I want to murder some prairie dogs this winter and next spring.

The boom stick

http://farm8.staticflickr.com/7295/9551659776_6e215e33a3_b.jpg (http://www.flickr.com/photos/94844416@N02/9551659776/)
MK12ModWormydog-11 (http://www.flickr.com/photos/94844416@N02/9551659776/) by wormydog1724 (http://www.flickr.com/people/94844416@N02/), on Flickr

[decodeddiesel]

I know the whole PRI rail thing is very dated, but man it looks sharp. Kudos to you for coming up with something so original. That is seriously an awesome one-off custom build right there!

Have you gotten around to weighing your rifle yet? I'd be really interested to see where you are at compared to a "real" MK12 MOD0.

[Wormydog1724]

I know the whole PRI rail thing is very dated, but man it looks sharp. Kudos to you for coming up with something so original. That is seriously an awesome one-off custom build right there!

Have you gotten around to weighing your rifle yet? I'd be really interested to see where you are at compared to a "real" MK12 MOD0.

I appreciate the kind words.

I'll weigh it when my nightforce scope arrives.
Thanks.

[rdbse]

I'll weigh it when my nightforce scope arrives.


Should be there any day:)

Nice build by the way!

[mdmorrow]

Nice looking rig! You can definitely tell you put a lot of thinking into it.

[Alaska3006]

I appreciate the kind words.

I'll weigh it when my nightforce scope arrives.
Thanks.

My MK 12 Mod O weights about 10 lbs with ammo minus can

[lahunter57]

What power range for the optic would you recommend? I've been looking at the NF 2.5-10x42 and the Leupold MK6 3-18 and I know they are two completely different types of scopes but they are almost the same size and weight. Do you think the Leupold would be too much optic for a 5.56?


Sent from my iPhone using Tapatalk

[TahoeLT]

They were issued with 3-9x, 2.5-8x, 3.5-10x and 2.5-10x. Any of those are good scopes, but civvie requirements are different from military ones. I run a 3-9x on one of mine, and a 3.5-10x on the other; and if I wasn't trying for a military Mk12 replica I wouldn't mind more magnification!

I guess it depends on your eyes and skills. I can run out to 700m + with Mk262, and 10x is decent for man-sized targets.

[Alaska3006]

Suggest Leupold mk 4 2.5x8 tactical that is made for the MK 12

[lahunter57]

i understand. I'm not going for an exact replica but I want it to be close while still being light and adaptable. I want it to be able to take some abuse, which is why I'm leaning towards the NF. I've only shot past 500 a few times and that was a 10x and it was plenty. Theres not too many places to stretch out around here.

[Wormydog1724]

I'd say go with the NF. It just looks right and is plenty of optic for 5.56.

https://farm4.staticflickr.com/3698/12140880354_e0739fef21_b.jpg (https://www.flickr.com/photos/94844416@N02/12140880354/)
MK12-5 (https://www.flickr.com/photos/94844416@N02/12140880354/) by wormydog1724 (https://www.flickr.com/people/94844416@N02/), on Flickr

[lahunter57]

I agree, i definitely like the look and the features/ruggedness that come along with it. Now to figure out which unimount will clear buis.

[Wormydog1724]

If you're doing a mod 0, I went with the low profile PRI rear sight and ARMS medium #22 rings. Not exactly spec, but close.

[lahunter57]

Im running a centurion CMR so I'm definitely not in spec and that wouldn't work for me since you're running the swan sleeve. My build was inspired by the MK12, I'm just not following it closely.

[Wormydog1724]

Yep you're right.

In that case I'd go with some KAC buis and a LaRue LT104 or LT139.

[Alaska3006]

If you're doing a mod 0, I went with the low profile PRI rear sight and ARMS medium #22 rings. Not exactly spec, but close.

I went with Med 22 rings and 40L SP ARMS rear sight
Ts30 A2 leupold 2.5 x8

Have a tactical 3.5 x 10 but seemed to balance out better with the 2.5x8 tactical MK4
For 77gr range this 2.5 x 8 power works just fine

I will mount a Docter Sight on top of the scope with American Defense mount on the Arms Base.
I used the A5 rear extension with the B5 stock from the SOPMOD kit from the Army.
Most everything is PRI with the Douglas Barrel

[henschman]

I like it... I always prefer to have the front sight attached to the barrel rather than the handguard too. I just don't like the idea of my front sight floating independently of the barreled action.