Mk262 Mod1 load info

[NJC]

Guys looking for load and component infor on the 77gr Mk 262 Mod 1 5.56 round.

I need the actual spec if it is available, a link would be cool.

Here I what I know

Projo : 77gr Sierra OTM round with cannelure

Powder : ?

Primer : CCI military ?

Brass : Black Hills or ?


Also source for components would be great. Thanks

[Rumbler]

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.

http://www.223reloads.com/home/223-5-56-info/223-5-56-reloading/duplicatingnato


:)

[Rumbler]

Oh, one last thing NJC,

Do not ever try and duplicate a military loading in commercial brass.

Commercial brass is thinner in places that it needs to be as thick. :)

[Airgator0470]

This chart indicates 24.5 grs. of TAC.

I've had great success using Re15 and AA2520.

Using LC brass, Rem Bench Rest Primers, and 23.5 grs. of AA2520, I'm hitting an average of 2765 FPS and get well under MOA, best so far for a 5-round group in my 18" WOA SPR was .575" at 100 and 1.5" at 300. Same load went .446" for 5 shots in my 20"BHW SPR.

** Your results may vary.

ALL LOADS USE MILITARY BRASS (except the 9 mm), AND
MILITARY BULLETS (OR THEIR COMMERCIAL EQUIVALENT).
REDUCE ALL LOADS BY 10% (EXCEPT THE LOAD MARK BY *) AND WORK UP





Military Ammunition Equivalents


Cartridge
Bullet Weight
(gr)
Velocity
f/s
Suggested load(s)



M41 .38
130
950±45
6.3 gr PowerPistol, 5.2 gr Unique or Universal


M882 9 mm
124
1230±50
6.4 gr Accurate #5, 8 gr BlueDot


M1911 .45ACP
230
820±25
5.2 Bullseye


M193 5.56 mm
55
3250±40
26 gr. of H335, 26.5 gr TAC


M855 5.56 mm [for 5.56 NATO chambers ONLY]
62
3020±40
26 gr of TAC


MK262 5.56 mm [for 5.56 NATO chambers ONLY]
77
2750±30
24.5 gr TAC


M80 7.62 mm
149
2750±20
42.5 IMR4895, 46 grs. 748 or Ball C2


M118 7.62 mm Special Ball
173
2550±30
43 grs. of RL15 or 748


M118 7.62 mm Special Ball LR (Sierra MK bullet)
175
2580±30
42.5 grs. of Varget,


M852 7.62 mm MATCH (Sierra MK bullet)
168
2550±30
41.5 IMR4895


M2 Cal .30**
150-152
2740±30
49 grs. IMR4895
49 gr 748
50 gr IMR4064


M72 Cal .30 MATCH**
173
2640±30
47 gr IMR 4895
47.5 gr 748
47.5 gr IMR 4064


M1 Cal .30 carbine
110
1900±30
14 gr 2400 or 14 gr H-110*


* Do not reduce H110 more than 3%
** Powders list are the best burning rate for use in the M1 Rifle

[SB]

That's good to know. Just scored an 8 pound jug if TAC and was wondering what range to work up to.

[NJC]

Thanks for all the quick responses.. i appreciate it...

Anyone found a good source for the components ?? anything local, how about powder how about TAC, RE15 or Varget ???

[Rumbler]

NJC, check DSH. I was in there recently and they were well stocked. Surprisingly so.

I even found BL-(C)2 !!!!! And that stuff has been as scarce as hens teeth for months. :headbang:


Oh yeah, and they did have Varget by the pound also. :cool:

[Airgator0470]

NJC, check DSH. I was in there recently and they were well stocked. Surprisingly so.

I even found BL-(C)2 !!!!! And that stuff has been as scarce as hens teeth for months. :headbang:


Oh yeah, and they did have Varget by the pound also. :cool:

Guys... I need AA2520 keep a look out. Do they have AA2520 by chance?

[NJC]

Bob, I will go monday and call you if I see it there..

[Rumbler]

I will be more than happy to check for you, Bob. I don't know off the top of my head. If they do I'll grab what I can of it for you.

[mapper]

I'm getting 2625 fps from a 20" wylde with 24.5 varget, 77 smk, lc brass, cci primer loaded to mag length..
I decided to stop there...good accurate load though..
Like others have said, start low and work up, your rifle will tell you what it likes..

[Capt. mike]

I picked up 77smks from DSH the other day but it may have been the last box, its over max for .223 but I used 25gr of CFE223 and they worked great in my 10.5" just havent had access to a chrono yet.

[Capt. mike]

I used hornady brass for some of my light loads and IMI 5.56 brass for the 77s but I have lots of LC brass just the primer crimps are a pain in the ass, I use a chamfer tool before I prime them but whats the cheapest ans easiest way to clean out the crimps, ill probably stick with LC brass if I start going hotter

[YankeeFingergasm]

Thanks for all the quick responses.. i appreciate it...

Anyone found a good source for the components ?? anything local, how about powder how about TAC, RE15 or Varget ???

There's 2 LBs of Varget in the Rumbler Auction FYI.

[JMW4570]

I used hornady brass for some of my light loads and IMI 5.56 brass for the 77s but I have lots of LC brass just the primer crimps are a pain in the ass, I use a chamfer tool before I prime them but whats the cheapest ans easiest way to clean out the crimps, ill probably stick with LC brass if I start going hotter

Get the Dillon Super Swage...

[Rumbler]

Get the Dillon Super Swage...


Amen! That gizmo is one of the best hundred bucks I have ever spent.:headbang:

[JMW4570]

Has anyone tried this? https://www.wideners.com/itemdetail.cfm?item_id=100001635&dir=

[Rumbler]

I have not. But you know IMI has as good a reputation for quality mil-spec brass as Lake City . . at least for the 7.62x51.

[Airgator0470]

I don't worry about using MIL brass any longer... I've used Rem, Win, Fed, and others with no observed differences... this is an interesting internal capacity/volume chart... maybe years past there was a significant difference but it does not appear so. Without cut-aways and the ability to view the actual web area, they all appear close.


http://imagizer.imageshack.us/v2/xq90/909/iJqW5k.jpg (https://imageshack.com/i/p9iJqW5kj)

[polebarn]

FWIW.

http://forum.snipershide.com/snipers-hide-reloading/197266-mk262-clone-77grain-5-56-load-problems-updated-ocw-tests.html

[Rumbler]

Bob I am not being a smart ass. At least not intentionally.

But . . . how is 1.2gr of internal volume not significant?

Really, it is not that I don't believe you - I know better than that shit. But I honestly do not understand and I am hoping that you can help me to.




I don't worry about using MIL brass any longer... I've used Rem, Win, Fed, and others with no observed differences... this is an interesting internal capacity/volume chart... maybe years past there was a significant difference but it does not appear so. Without cut-aways and the ability to view the actual web area, they all appear close.


http://imagizer.imageshack.us/v2/xq90/909/iJqW5k.jpg (https://imageshack.com/i/p9iJqW5kj)

[Cattle/Horses]

Rumbler, The LC brass has the highest capacity. If, as reported. it is thicker and the military standard, one would reason it should have one of the lowest capacities. At least that's what I took away from the chart.

[Airgator0470]

No problem Mike... fair question, if you look at the extremes: Lapua at 29.2 vs. LC at30.4, perhaps with those two cases one might be able to detect a noticeable difference as there is a spread of 1.2, ... but when you look at and consider the difference between the more common brands, Win commercial, WCC, Fed Tac, Hornady, and LC, it's only a spread of 0.4... insignificant in my opinion and experience as I get Hornady, Fed Tactical, and LC brass for free and have not encountered any pressure issues one way or the other.

Personally, I think the thick mil brass issue is an over inflated issue, not completely worthy of ignoring, but not enough to worry about. But each reloader must decide for themselves where to place additional caution. Me... I think using a true 5.56 or Wylde chamber is more important when trying to duplicate military-type rounds (true 5.56mm and MK262) than head stamps (granted you're using the ones above an not some obscure crap).

[Airgator0470]

No problem Mike... fair question, if you look at the extremes: Lapua at 29.2 vs. LC at30.4, perhaps with those two cases one might be able to detect a noticeable difference as there is a spread of 1.2, ... but when you look at and consider the difference between the more common brands, Win commercial, WCC, Fed Tac, Hornady, and LC, it's only a spread of 0.4... insignificant in my opinion and experience as I get Hornady, Fed Tactical, and LC brass for free and have not encountered any pressure issues one way or the other.

Personally, I think the thick mil brass issue is an over inflated issue, not completely worthy of ignoring, but not enough to worry about. But each reloader must decide for themselves where to place additional caution. Me... I think using a true 5.56 or Wylde chamber is more important when trying to duplicate military-type rounds (true 5.56mm and MK262) than head stamps (granted you're using the ones above an not some obscure crap).

Edit to add- Perhaps it's better stated this way... if 24.5grs of TAC shows specific pressure signs with Win commercial, I'd suspect the same will show if you change to Fed Tac... I think at that point, the chamber, powder, powder charge, and weather will be of more influence than the head stamp. Some of my good loads are using RP brass... and not the WCC or LC, who knows...

[Rumbler]

Thank you, Bob. I see your point. :smoker:

[Capt. mike]

Being a pretty modern powder isn't CFE223 a pretty stable powder temp wise? I know the way I shoot and the way I load temp stability is something I should pay attention to.

[Rumbler]

I am inclined to think so also. But in checking the Hodgdon website I see it is not a member of the "extreme" family. That is their group of temperature stable propellants.


http://www.hodgdon.com/new_prod.html

. . and . . .

http://www.hodgdon.com/extreme.html


So . . . . I dunno. :(