Reloading for the MK318 (5.56)

[goodlookin1]

Hey guys,

I bought 500 bullets pulled from Mk318 mod0 military rounds. These are the new rounds adopted by the USMC, which have shown lots of promise and praise reports thus far since adoption. What I cannot find is what kind of powder they are using to push the bullet. I'm not even sure what a good starting load is. I have TAC and Varget powders to reload with. Here's a picture I took of the different bullets lined up next to each other so that you get a good feel for how long it is:

From left to right: 75gr hdy HPBT, 68gr hdy HPBT, 69gr SMK, 62gr SS109, 62gr MK318, 62gr M193, 55gr AMAX



Based on the length and weight, I think it's probably pretty comparable to the SS109. I am thinking my max TAC load is going to be 25.5gr. Obviously I would work up to this load to be safe, but what I'm wondering is, what will be the best powder that will push this the fastest? I'm not primarily concerned with accuracy....that would just be a bonus. This will be used primarily as a defense load and not a plinking round. I'll probably develop the best load, test them, then store them for "a rainy day"

What do you think? Is TAC a good starting place, or should I get a different powder?

Thanks.

[goodlookin1]

Okay, no hits. Let me rephrase the question:

What is the fastest 5.56 powder for a midsized (60-68gr) projectile?

[joelogic]

Interesting question.

I chrono'd some factory M855 and it was going 3000fps out of a 16" barrel. What is the rated speed of mk318?

[fabguy]

I would think that a m855 would be a very good start, I am no expert though

[jimmykan]

FYI, the M193 projectile weighs 55 grains, not 62.

If you want to start with M855 loading data, I believe it is loaded with 26.1 grains of WC844 powder.

[goodlookin1]

FYI, the M193 projectile weighs 55 grains, not 62.

If you want to start with M855 loading data, I believe it is loaded with 26.1 grains of WC844 powder.

Thanks.

Oh and yes, I know the m193 is 55gr, but the bullet profile is the same as the true m193, just slightly longer and not by much. That is why I said 62gr m193, not just m193.....if you look at the armscor bullets (62 vs 55) side by side, there's barely a difference