Question on the MK262 and MK318 SOST.

[LastOfMyKind]

I'm sure this has been talked about before but I thought I ask anyway.

First how many grains of powder is the BH MK262 77 gr loaded with?


And if the new open tip MK318 5.56 62 gr SOST used by the USMC is getting 2925 fps out of a 14.5 barrel, what kind and how much powder are they using? If its a powder blend then how much?

 

[LastOfMyKind]

Re: Question on the MK262 and MK318 SOST.

Eh anyone?

 

[tnichols]

Re: Question on the MK262 and MK318 SOST.

I've never pulled a bullet to find out. I'm running low on it, so I probably won't either. It is loaded pretty snotty though, as the lot I'm shooting now chronoed at 2850 out of my 24" piped Bushmaster.

 

[2ndPanzer]

Re: Question on the MK262 and MK318 SOST.

its a powder from St. Marks, and we can't get it. The Alient power pro powders are supposed to get us close.

 

[Jason280]

Re: Question on the MK262 and MK318 SOST.

Regardless of the charge weight, its going to be a powder not available to the general public. Meaning, even if you know the exact charge weight, it won't make much difference. Now, its possible to work up a similar load using available powders, but it won't be with the current .mil powders.

24.5gr of Varget behind 77gr SMK's will get you close, but it won't be the same

 

[LastOfMyKind]

Re: Question on the MK262 and MK318 SOST.

So does the MK 318 and M855 have the same charge weight even though they use different powders?

 

[Jason280]

Re: Question on the MK262 and MK318 SOST.

Its doubtful they even use the same powders, much less the same charge weight.

 

[bfoosh006]

Re: Question on the MK262 and MK318 SOST.

http://www.dtic.mil/ndia/2009infantrysmallarms/tuesdaysessioniii8524.pdf ....page 21..

"Short barrel propellant was specifically designed for this cartridge configuration"

 

[LastOfMyKind]

Re: Question on the MK262 and MK318 SOST.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bfoosh</div><div class="ubbcode-body"> http://www.dtic.mil/ndia/2009infantrysmallarms/tuesdaysessioniii8524.pdf ....page 21..

"Short barrel propellant was specifically designed for this cartridge configuration" </div></div>

So what does that mean about the charge weight?

 

[Jumper]

Re: Question on the MK262 and MK318 SOST.

It means that they went to the powder manufacturer with their parameters for burn rate, pressure volume etc., and said "make this powder. We will buy 5 million pounds." The powder manufacturer said "OK" and formulated a new powder that met the needs of the military.

It means it makes the charge weight irrelevant because you can't get the powder. Unless you buy 5 million pounds of it.

 

[azemspilot]

Re: Question on the MK262 and MK318 SOST.

Powder used:

The powder used to load these rounds is not available for retail. This is not because it is some top-secret, magical mystery powder. Commercial and military powders are made in huge lots, each with a slightly different burn rate than the other. Retail canister powders are blended to be very uniform lot-to-lot, for liability and marketing purposes. That way the loading manuals stay accurate.

Charge weight:

Even though there may be a govt. specified charge weight, it is only a reference. Because each lot of powder is different, a different load is worked up for each, resulting in different charge weights from lot-to-lot. This is done to meet velocity and trajectory requirements.

That being said, almost any military or commercial load can be duplicated or improved using off the shelf canister powders. They cover a very wide spectrum of burn rates and volumes. For MK262, Varget seems to be the powder of choice, mostly because of its temperature insensitivity. This is important when working at the very edge of a cartridge's pressure and velocity envelope. RL15 and Tac are very good too, especially in cooler climates. Also, Tac meters the best through progressive machines.

As for loads with available powders:

http://www.snipershide.com/forum/ubbthreads.php?ubb=showflat&Number=887960

and some more:

http://media.ar15.com/media/viewFile.html?i=9862

The accepted recipe for MK262 tends to be from 24-25 grains of Varget with a 77grain SMK. These are 5.56 loadings, not .223, and must be worked up to, with a reduced starting load.

I have not attempted to replicate MK318. However, I am sure it could be done, using the faster powders appropriate for 5.56.

I hope this helps.

 

[azemspilot]

Re: Question on the MK262 and MK318 SOST.

Battlestar Galactica fan, it seems you have been preoccupied with charge weight:

http://www.thehighroad.org/showthread.php?t=507076

Many of us have said charge weight is irrelevant, if you don't know or can't purchase the powder. We really do know what we are talking about.

 

[LastOfMyKind]

Re: Question on the MK262 and MK318 SOST.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: AZ EMS Pilot</div><div class="ubbcode-body">

I have not attempted to replicate MK318. However, I am sure it could be done, using the faster powders appropriate for 5.56.

I hope this helps.

</div></div>

Yes you helped a lot, however I don't think they use faster burning powders for the MK318 because they are able to get 3025 fps out of a 20in barrel from an M16 and in order to do that you need to keep the pressure up until it leaves the barrel something that slower burning powders do well.

I think Federal is doing something like Hornady is for the superformance, same charge weight but more effective powders that burn completely giving you 100-200 fps faster out of both long and shot barrel rifles.

Edit: the .223 and 7.62x39 on average have 24-26 grains of powder for both....interesting.

 

[LastOfMyKind]

Re: Question on the MK262 and MK318 SOST.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Jason280</div><div class="ubbcode-body">Its doubtful they even use the same powders, much less the same charge weight. </div></div>

They don't, the MK 318 from what I read has a powder blend, getting 2925 fps with a 62 gr out of a 14.5 barrel gives me the impression that the MK318 has a higher charge weight but also a more effective powder as well.

 

[Alan Griffith]

Re: Question on the MK262 and MK318 SOST.

Baltar,

Do you want to make your own Mk 262? I did and still do. I use the Hornady 75 bthp Match and hit 2750 from a 16" RRA barrel.

Alan

 

[bfoosh006]

Re: Question on the MK262 and MK318 SOST.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Jumper</div><div class="ubbcode-body">It means that they went to the powder manufacturer with their parameters for burn rate, pressure volume etc., and said "make this powder. We will buy 5 million pounds." The powder manufacturer said "OK" and formulated a new powder that met the needs of the military.

It means it makes the charge weight irrelevant because you can't get the powder. Unless you buy 5 million pounds of it. </div></div>

Thanks Jumper.

 

[Lindy]

Re: Question on the MK262 and MK318 SOST.

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">It means it makes the charge weight irrelevant because you can't get the powder. Unless you buy 5 million pounds of it.</div></div>

I wonder if they accept MasterCard or Visa...

 

[LastOfMyKind]

Re: Question on the MK262 and MK318 SOST.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: GSSP</div><div class="ubbcode-body">Baltar,

Do you want to make your own Mk 262? I did and still do. I use the Hornady 75 bthp Match and hit 2750 from a 16" RRA barrel.

Alan </div></div>

That and the MK318 from a 14.5 in barrel.

 

[Alan Griffith]

Re: Question on the MK262 and MK318 SOST.

Baltar,

I can help you develop a Mk 262. Mine will keep 10 in 10" @ 600 yds in 20 F Deg temps with a 1:9 twist barrel using a 2x ACOG.

 

[LastOfMyKind]

Re: Question on the MK262 and MK318 SOST.

This is similar to the MK318, I was reading about the Army's new M855A1 LFS (lead free slug) and it also has increased muzzle velocity, improved propellant and reduced muzzle flash.

If the new M855A1 LFS is just part of the M855 family does that mean it still has the same powder charge as the M855 or is it the same story like with the MK 318 SOST round?

 

[bigwill214]

Re: Question on the MK262 and MK318 SOST.

Just out of curiosity, I understand the need/want for super accurate ammunition but I am failing to fully understand the fasination with the military rounds. Throw a dog a bone here, what is it that I am missing??

 

[2ndPanzer]

Re: Question on the MK262 and MK318 SOST.

Ninja factor...

 

[LastOfMyKind]

Re: Question on the MK262 and MK318 SOST.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 2ndPanzer</div><div class="ubbcode-body">Ninja factor...

</div></div>

Ninja factor?

 

[bigwill214]

Re: Question on the MK262 and MK318 SOST.

I thik that the point that Panzer was making is that the rounds are military rounds and do not have some special mojo that will make them do any better than a load that is worked up by a reloader. Not even the AMU uses those rounds for matches. They have theirs hand loaded. All of them. Trust me I've seen the warehouse. They use SMKs and VitaVourhi (however it's spelled) powder. You will also find that some of the best is Federal GM or BH rounds.

 

[bigwill214]

Re: Question on the MK262 and MK318 SOST.

Can always try these too.

http://www.ssarmory.com/556ammunition-2.aspx

 

[hitman]

Re: Question on the MK262 and MK318 SOST.

I load 25 grains of TAC and 77 SMK's. But this is WAY over max so work up to it. I did in all my 5.56 chambered rifles and they are fine and no excessive presure signs. Cronos right at 2750 out of a 16" Noveske. Hope that helps.

 

[archad]

Re: Question on the MK262 and MK318 SOST.

I have loaded 24.7 of Tac and 77gr Noslers and got 2634 fron a Noveske Afghan(14.5")