MK262 mod 1 load data help

[Tigereye]

I recently got some XBR and finally loaded up a few to test today. Mark recently told me about the 23.4gr with Wolf SRM load for 77gr SMK's and I've been following this thread. Today I shot 77gr SMK with 23.1gr of XBR and Wolf SRM primers with 3/8" group size at 50 yds. I also shot 23.4gr with 5/8" group at
50 yds. Haven't chronoed them yet and hope to shoot at 100 yds on Sat. I'm shooting a DD V1 with a Vortex 1-4.

[Clemonsds]

I am going to load a few higher just to find my barrels sweet spot. it seems like 23.1 is doing great for you. Let me know what you chrony it at. Your group might open up some at 100 yards.

Mark has been very helpful with the information he has given. Hope mine has been half as much help as his with the addition of the result of the black hills MK262 I chronographed.

[Tigereye]

Somedays are really good trigger days. DDV1 with Vortex PST 1-4 shooting the 77gr SMK's with 23.1gr of XBR. One 5 shot group was just under 1/2" with another group of 3/4" at 100 yds. I also chronoed 10 rounds with an average of 2,652fps. I think I've found a load that my gun likes. I'm also liking the SSA trigger.
Thanks guys for all your help.
Eric

[Clemonsds]

I had debated gong with the SSA trigger but chose timney 3 pound instead. That's some good groups, and about the same average velocity I'm getting.

I did some 300 yard shooting with the black hills 69 OTM a couple days ago and it grouped 1.58 inches.
With a zero of 100 yards, my optics are adjusted up 1.5 moa for 200 yards, and plus 2 moa for 300 yards(3.5 moa from zero)

[ride57]

Hi, saw the thread title and remembered I had come across some loads. It is from 223reloads.com, duplicating nato cartidges section (http://www.223reloads.com/home/223-5...uplicatingnato) everything below is copied from that website.

"If you want an MK262 mod 1 duplicate, try:

77gr Sierra Match King, 25.3gr Varget, CCI 400 primer, and LC brass - NOTE: THIS LOAD EXCEEDS SAAMI SPECS. USE IN NATO OR WYLDE CHAMBER ONLY. USE AT OWN RISK. - 2780~ fps in an 18" SPR barrel

FYI: Nosler 77gr will shoot a little faster than Sierra 77gr with the same powder charge. It is probably due to the fact that the Nosler has a shorter base to ogive length and thus has less bearing surface with the bore."

"I exactly duplicated the M262 load with TAC, but it is very hot and I changed to N540.

It was 26 grains of TAC driven by a Magnum Primer with the Nosler cannelured 77 grain bullet. This came out at over 2750 fps from a 16 inch barrel. I didn't have a problem with it but some of the primers were flattened.

To dup the M262 using available powder I use the much more expensive N540 and Varget.

That said I use more TAC than any other powder because there is no reason to load this hot for plinking, triggertime, drills, and even shtf with 62 grain bullets.

For TAC I suggest 25 grains with a normal primer driving 62 grain bullets. That will more than approximate M855 and be easy on your gun. I load 2 different 62 grainer bullets, pull down M855 and Golden West 62 grain with cannelure.

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There have been posts on Mk262 recipes before. I've posted the one I developed for my 18" SPR when I still had it.

NOTE: The following data exceeds SAAMI specifications and can be dangerous to use in certain rifles.

Sierra Match King 77gr BTHP
25.3gr Hodgdon Varget
LC Brass
Winchester SR Primer

Developed in a White Oak Armament 18" SPR configuration with a Wylde chamber.

Note: At the time, I was using Winchester SR primers. I would recommend Remington or CCI instead.

Any load that will give you Mk262 performance will exceed SAAMI specifications for .223. Thus, you're not going to find any published commercial data that will meet Mk262 velocities.

You shouldn't use anyone's Mk262 'recipe' straight up.

If you want to make your own Mk262 clone ammo, you NEED to get a chronograph and work up the load appropriately. Don't kid yourself thinking you can just use someone else's recipe or the commercial data and guestimate the proper load to meet a specific velocity. The Mk262 pressures/velocities are pretty hot and you're going to need to carefully find the right load for your specific rifle. And when you do find the correct load for your specific rifle, you need to reconfirm the load every time you go to a new lot # in bullets, powder, primers, or cases.

Also, that Nosler load quoted as mine was not confirmed to be 2650fps in an 18". That is my load I use in Service Rifle and it clocks 2740fps in a 20" Service Rifle barrel. I would estimate that it shoots 2650fps in an 18", but I have never clocked it in a 18" barrel.

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Ramshots 5.56 data for the 77gr bullets show (20" barrel)

Bullet weight: 77 grain HP.
Start load: 22.1 grains (2525 – 2625 Ft/p/sec)
Maximum load: 24.5 grains (2750 – 2850 Ft/p/sec). <62000 Psi"

[Clemonsds]

Test, test, test, test, and test some more. That's reloading when it comes to developing a hand load just for your specific rifle/pistol.

[Whiskey&beer]

If you really want to duplicate MK262 then I'll just say again - buy a box or two of the actual 262, chrono it out of your rifle so you know exactly what speeds to look for, and go from there. If you don't know what 262 shoots out of your rifle, then your chasing speeds that could / probably be wrong and you could be going way too hot. Reading to do a load of 26gr of Tac and getting speeds 2750 out of a 16" barrel is way over pressure and that will end up being more than a flattened primer issue. Mk262 does Not shoot that fast out of a 16" and is usually in the mid 2600's. Almost hitting a velocity of 2800 out of a 18" barrel with 77's is way too fast and is in dangerous pressure levels, but hey... It's not my gun nor will I ever be behind that type of load pulling the trigger.

Now I'm not trying to sound rude and I don't really care what people want to do with their loads but I just hope people do things right to avoid unneeded risk.

[Clemonsds]

Who are you telling that too?

[Whiskey&beer]

Hey Clemomsds - sorry but that wasn't directed at you in any way. You're doing damn fine on your loading / shooting so don't mind me! I read a post where I seen way heavy of loads so I made a comment. I'd just hate to hear someone do a load that could potentially get someone hurt.

[ace4059]

Ramshots 5.56 data for the 77gr bullets show (20" barrel)

Bullet weight: 77 grain HP.
Start load: 22.1 grains (2525 – 2625 Ft/p/sec)
Maximum load: 24.5 grains (2750 – 2850 Ft/p/sec). <62000 Psi"

This is my mk262 recipe.
Brass: LC trimmed 1.750
Bullet: Nosler 77 gr Custom Competion
Primrs: CCI #41
COAL: 2.255 with a light crimp.
Powder: Ramshot TAC

23.0 gr. was the best accuracy. 1/8 moa was the best three shot group I was able to achive. 1/4 MOA was average.
23.5 gr. is my general purpose load for shooting 600 yrds. right about 2700 fps and 1/2 moa.
24.1 gr. I was able to achieve 2750 fps average
24.5 gr chronoed right at 2790-2800. But accuracy suffered and groups opened to 1 moa
24.8 gr is what I use for hog hunting. The nosler cc bullet has explosive results.
25.0 gr loads I started seeing pressure signs of flattening primers.

AR-15 has a 20" Shilen SS barrel 1/8 twist with 223 Wylde chamber.


Best 3 shot group at 100 yrds