Why do we love the MK12 so much?

Where's the pics of this thing?
Ask and ye shall receive.

A.R.M.S #22 rings are on backorder, so yeah...
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16" vs. 18" = free velocity, which increases effective range.
18 SPR Mk. 262 2750fps mv, sea level SA

325yds 2057fps 724ft-lbs......... 1.3 mils drop/ .9 Mils drift (for full value 10mph)

600yds 1503fps 386ft-lbs.........4.4 Mils drop/ 1.9 Mils drift

(9mm muzzle energy is anywhere from 295-500ft-lbs at the muzzle, most are in the mid-350ft-lbs region.)

16” Recce 2700fps mv, same load/conditions

325yds 1974fps 666ft-lbs........... 1.5 Mils drop/ .9 Mils drift

600yds 1469fps 369ft-lbs.......... 4.8 Mils drop/ 2 Mils drift

14.5” SOPMOD Block II 2633fps mv, same load/conditions

325yds 1918fps 629ft-lbs...........1.6 Mils drop/ 1 Mil drift

600yds 1426fps 348ft-lbs.......... 5.1 Mils drop/ 2 Mils drift

You start to see why guys stopped taking the SPRs outside the wire and just going with Block II SOPMOD with a good trigger, optics, and can.

iu


iu


18” SPR is great for shooting suppressed/prone/bipod supported, or tripod-supported in urban hide.

It’s a 100% of the time weight/length penalty for no real practical ballistic gain over the shorter guns.

I notice a handling under recoil advantage to a RLGS suppressed 18” SPR vs a CLGS SOPMOD suppressed for sure though. ILGS or correctly ported and tuned MLGS 16” or 14.5” can be made to perform really close as far as cyclic rate and recoil/muzzle climb.

The 18” SPR is great for learning on for new shooters to intermediate/long range if they don’t have any experience with wind-reading, even better than .308 since you can spot your own hits and the BC is so low that you really need to read and hold for wind to get hits.

If the wind conditions are around 10mph or higher, it’s hard to hear or see your impacts even at 450yds, unless you have really lightweight/smaller plates that will move. Most here know how anemic 9mm is at moving plates at close range, so you have to be able to perceive those hits at distance when you make them. In calm wind conditions, you can hear the impacts quite clearly even out to 600yds, but those times are extremely rare.

Short story is 5.56 even with 77gr just doesn’t retain a lot of energy once you get out beyond 200-300yds, load/barrel length dependent.
 
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It’s a 100% of the time weight/length penalty for no real practical ballistic gain over the shorter guns.

I think that’s why the “mini recce” concept is becoming so popular. You get most of the performance without many of the down sides. With modern LPVOs and good bullets, the short guns are surprisingly capable while still being convenient.


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I think that’s why the “mini recce” concept is becoming so popular. You get most of the performance without many of the down sides. With modern LPVOs and good bullets, the short guns are surprisingly capable while still being convenient.


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And looks cool, 15.1" barrel? What NF? I am debating cutting my BA barrel or just order one. Nice rifle. Lot of open real-estate too
 
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18 SPR Mk. 262 2750fps mv, sea level SA

325yds 2057fps 724ft-lbs......... 1.3 mils drop/ .9 Mils drift (for full value 10mph)

600yds 1503fps 386ft-lbs.........4.4 Mils drop/ 1.9 Mils drift

(9mm muzzle energy is anywhere from 295-500ft-lbs at the muzzle, most are in the mid-350ft-lbs region.)

16” Recce 2700fps mv, same load/conditions

325yds 1974fps 666ft-lbs........... 1.5 Mils drop/ .9 Mils drift

600yds 1469fps 369ft-lbs.......... 4.8 Mils drop/ 2 Mils drift

14.5” SOPMOD Block II 2633fps mv, same load/conditions

325yds 1918fps 629ft-lbs...........1.6 Mils drop/ 1 Mil drift

600yds 1426fps 348ft-lbs.......... 5.1 Mils drop/ 2 Mils drift

You start to see why guys stopped taking the SPRs outside the wire and just going with Block II SOPMOD with a good trigger, optics, and can.

iu


iu


18” SPR is great for shooting suppressed/prone/bipod supported, or tripod-supported in urban hide.

It’s a 100% of the time weight/length penalty for no real practical ballistic gain over the shorter guns.

I notice a handling under recoil advantage to a RLGS suppressed 18” SPR vs a CLGS SOPMOD suppressed for sure though. ILGS or correctly ported and tuned MLGS 16” or 14.5” can be made to perform really close as far as cyclic rate and recoil/muzzle climb.

The 18” SPR is great for learning on for new shooters to intermediate/long range if they don’t have any experience with wind-reading, even better than .308 since you can spot your own hits and the BC is so low that you really need to read and hold for wind to get hits.

If the wind conditions are around 10mph or higher, it’s hard to hear or see your impacts even at 450yds, unless you have really lightweight/smaller plates that will move. Most here know how anemic 9mm is at moving plates at close range, so you have to be able to perceive those hits at distance when you make them. In calm wind conditions, you can hear the impacts quite clearly even out to 600yds, but those times are extremely rare.

Short story is 5.56 even with 77gr just doesn’t retain a lot of energy once you get out beyond 200-300yds, load/barrel length dependent.

Im not sure why you have to come in here with all your factual information causing heartburn for my emotional bias towards MK12s and MK18s. Rude I’d say.
 
Im not sure why you have to come in here with all your factual information causing heartburn for my emotional bias towards MK12s and MK18s. Rude I’d say.
I will still say that the 18” SPR suppressed is one of the most pleasant AR-15 set-ups to shoot from the prone/bipod-supported, as well as tripod-supported positions. It’s just not as pleasant to carry as a 14.5” SOPMOD Block II or 10.25” CQBR-equipped shorty.
 
I have sold custom bolt guns, an AI, a couple ARs, and the only one of them all the regret selling was a clone correct MK12MOD1.

Thing was stupid accurate. 3/3 at 650yards
View attachment 7556916

Yes it was a pig, bud man was she accurate for a 223 gasser. The 2.5-10x24 was less than ideal in my opinion for it, so I upgraded to a MK6 3-18 and I felt the 3-18 served it a lot better than the 2.5-10.
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Same I sold my MK12 Mod 1 and have been regretting it since. I never got an AEM5 but given that i dropped an absurd amount on a FA762SS for an XM3 clone the AEM5 looks hella cheap right now as far as building clones. The only negative about it to me was how heavy it was for an 18" rig it was just unwieldy. Extremely fun to shoot either way. But yeah I really miss that rifle.
Mod H is the only clone I kept. Probably never part with it. View attachment 7565994
I was today years old when i found out there was a Mod H and it's now on the to build list. I think I'm going to do a Mod H and put a 2.5-10 credo on it. What does your Mod H weigh out of curiosity?

IMG_0167.JPG
 
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Yeah, these rifles are absolute sweethearts to shoot supported, especially with the can (that's an Ops Inc 12th Model I got in 2009) I am still on the fence about changing the gas block from the Superlative, but that's pretty simple. Lower is an old (ca. 1988) Essential Arms A1-ish piece. The 2.5-10x24 is an NPR2 moa/moa instead of Mildot, but it works surprisingly well in its simplicity. I have an A1 buttstock for it, but normally have the A2 stock on it with a Medesha adjustable buttplate for added LOP.
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My wife ringing steel before I had the KAC rail. Now she calls it "her rifle" :rolleyes::cautious::
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Even Terry Houin said (about 1:14:00) he would still carry his Reece rifle. He slips and says "John" built the rifle for him. Pretty sure I know the "John" he's talking about. Same guy invented the L-shaped lug on the front of the pre-MK13 300/700 winmag rifles. He also welded a set of the "Navy" lugs onto my M1A. Hell of a great guy and innovator.

Instead of doing a Reece rifle, I did a medium-weight "Hansen" profile BA 1:8 14.5" barrel, mid-length gas on my carbine. My can on that is a local (Dave Wells) manufacturer and attaches via AAC 51T brake (p&w, of course 🤞). Combined with 3 tungsten weights in the buffer and a Timney 3# single stage, this rifle is butter-smooth and easily gets moa accuracy out to 400 with my 2750fps 75gr/8208 ammo.
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I forgot how much fun these 223 SPRs are to shoot. I had not shot my 18” WOA SPR in awhile. It took it out and had a blast getting good hits on steel from 400-800yds.

This gun started out as a pretty close to clone correct mod0 years ago, but I stripped it down and modernized it a few years ago.

I miss the look of the PRI tube and ARMS rail, but the URX4 is a much better rail.

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She's just about in final configuration. Got the lower back from cerakote today. Graphite black was the correct choice. Sinner Mass Fabrications in San Antonio, TX. Great group there.

View attachment 7622395

Looks great. I had to go with higher rings to get a good cheek weld. Used a 22MOA badger riser and .88 Badgers with the M3 and the 32mm NCS and use 1.3” Nightforce with the 24mm NXS.
 
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Looks great. I had to go with higher rings to get a good cheek weld. Used a 22MOA badger riser and .88 Badgers with the M3 and the 32mm NCS and use 1.3” Nightforce with the 24mm NXS.
I'm still waiting for ARMS 22 rings I ordered back in like February. 😟 The Leupold I have in there is OK, but the reticle stadia are a bit too thick for my liking (VX-Freedom AR 3-9x40 Tri-Mil red FireDot). May need to get a mo-betta optic. Not gonna go full clone but probably the NF NXS 2.5-10x32 Mil-R.
 
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I'm still waiting for ARMS 22 rings I ordered back in like February. 😟 The Leupold I have in there is OK, but the reticle stadia are a bit too thick for my liking (VX-Freedom AR 3-9x40 Tri-Mil red FireDot). May need to get a mo-betta optic. Not gonna go full clone but probably the NF NXS 2.5-10x32 Mil-R.

I got my riser in trade from a guy who worked the sniper locker at Campbell. They needed an extended rail and I needed a riser. Best deal the .gov ever got ;)
 
I'm still waiting for ARMS 22 rings I ordered back in like February. 😟 The Leupold I have in there is OK, but the reticle stadia are a bit too thick for my liking (VX-Freedom AR 3-9x40 Tri-Mil red FireDot). May need to get a mo-betta optic. Not gonna go full clone but probably the NF NXS 2.5-10x32 Mil-R.
where did you order the rings from?
 
Mounting Solutions Plus

AND

U.S. Tactical Supply.

Both showed in stock at time of order. A day after I ordered, got email saying, it was an inventory slip-up and it's on backorder
shit, ordered a set of mediums this weeked. Showed in stock too. I need to call to see if they have a set of medium NF rings. I'll just use that on my Mod H and move my 22s over to my Mod 0 build.
 
I use my Mk 12 rifles for varmint hunting and deer hunting as well as deer culling on permit. Though the difference seems small on paper, the killing effect is a great deal better than 16” rifles and less than 16” are basically worthless in my experience.

I own and like the 11.5” AR’s but they simply do not get it done. Every time I forget that lesson and try again I get a hard reality check.
I’m sure that will offend many but that is what I see over and over.
 
Short story is 5.56 even with 77gr just doesn’t retain a lot of energy once you get out beyond 200-300yds, load/barrel length dependent.

Eh going by napkin math at 500-600 you still have around the same or more energy as your typical CCW pistol and tons of people trust their lives to those. Agreed on everything else which is why I sold both of mine, ended up with 2900 bucks in my pocket and still have a 16" 223 that is a great plinker at the same distances.
 
Eh going by napkin math at 500-600 you still have around the same or more energy as your typical CCW pistol and tons of people trust their lives to those. Agreed on everything else which is why I sold both of mine, ended up with 2900 bucks in my pocket and still have a 16" 223 that is a great plinker at the same distances.
I count on a CCW pistol to put someone down with a rapid 3-7rd string dumped into them within a few seconds, whereas with a single round they might not even notice. If you can run the trigger/sight picture on a partially-exposed person at 500-600yds with an SPR, sure. I can do that on full-sized IPSC sils, but it gets pretty difficult to do it on partial exposures. Now if the partial exposure is the head, then a single or double should do the trick. Barriers and solid anchors on people past 200-300 are where it struggles. Within those distances, 5.56 is proven.

If you shoot the 77gr SMK or 73gr ELD-M in 5.56 from an 18” SPR, you can get 355ft-lbs out to 620yds.

The 6mm ARC in an SPR will more than double that energy at those distances with less chamber pressure. (well into the 720ft-lb + region)

6.5 Grendel SPR will be even more retained energy (780-805ft-lbs). 6mm will hit faster than any of them, so it has the momentum advantage.

Guys that have done 6.5 Grendel SPRs or 6mm AR/6mm ARC SPRs really enjoy them.

A big consideration for both military and civilians is ammunition commonality between those left and right of you, so 5.56 has its place for that reason.
 
I would hope an outfit like TBAC would buy the rights and continue to produce either the same can and brake/collar or this can in Ti. I absolutely love the AEM5.

Ron’s been in the game a long time, along side many of the names a lot of people here and in the mk13 thread know. He deserves to enjoy himself. The man has been supporting the military and the greater shooting community for years and I’m sorry to see him hang up the spurs but happy he’s going to have a chance to enjoy himself.
 
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Pretty sure both of Phil Seberger's (RIP) silencer patents (4907488 and 4576083) have expired. If a company out there thinks there is enough demand to support reverse engineering a 12th Model/AEM5, they probably will do so in Ron's absence.
 
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Even without ear pro, under a corrugated metal roof.... everyone else on the line couldn't believe it.

The sonic crack of my 77s still sting my ear the first few shots but nothing can stop that. I often wonder if this can in Ti would improve it but ultimately I think it would I probably just be lighter.

Per Ron, try to get at least 7 full turns of tightness. Most barrels only allows 2.5-4 turns. He advised to go 7-10 turns if you can. (We profile our own blanks). I had Tim adjust my collar shoulder to accommodate 7 - 10 turns on each barrel after that . That said, I shot probably 1000 rounds through an 18” and a 20” with just 2-3 turn until it was right and I never had a problem, but hat was range queen shit not any two way stuff.
 
The sonic crack of my 77s still sting my ear the first few shots but nothing can stop that. I often wonder if this can in Ti would improve it but ultimately I think it would I probably just be lighter.

Per Ron, try to get at least 7 full turns of tightness. Most barrels only allows 2.5-4 turns. He advised to go 7-10 turns if you can. (We profile our own blanks). I had Tim adjust my collar shoulder to accommodate 7 - 10 turns on each barrel after that . That said, I shot probably 1000 rounds through an 18” and a 20” with just 2-3 turn until it was right and I never had a problem, but hat was range queen shit not any two way stuff.
I'm at 7.5-8 turns. And yeah the supersonic crack is the only thing that stings for a few shots.
 
Call Capitol Armory. I emailed them Friday night after a member at ARF told me he pre-purchased one and Jorge called me yesterday. You have to pay all up front but they should be in by the end of the summer. I talked to Ron after hearing about his retiring, because I wanted to know if the cans were going to become unobtainable like the surefire FA762SS was. He said no they are not going away anytime soon that you should be able to get one in the next 2-3 months.
 
I came here to see if I could convince myself I need to finally build my spare AR15 lower but I think after reading this I’ll just spend that money to keep my Gen II AR10 fed.

That being said, I agree that the Mk12 is iconic but with the caveat that it’s iconic amongst veterans, somewhat aged long range enthusiasts and the ARFcom mall ninjas. Ie, not iconic within GenPop.
 
That being said, I agree that the Mk12 is iconic but with the caveat that it’s iconic amongst veterans, somewhat aged long range enthusiasts and the ARFcom mall ninjas. Ie, not iconic within GenPop.

That’s a good point. You should sell me that lower and any upper parts you’ve accumulated. I’ll put together a 14.5” to go along with my 16” Recce, 18” SPR and 20” “Mod20”. Or just do another 18” and gift the upper to my Daughter and Son in Law.

Or, I could build my first Mod1 🤔
 
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