Trying to Build Accurate load for Sig 556

[AntlerAddict]

I am a proud new owner of a sig 556 swat. I've enjoyed hunting and shooting all my life, but i am fairly new to reloading. I'm trying to develop an accurate hunting load for my 556. (I don't need to hear that the 5.56 can't handle hunting) I've decided to use a 70gr Barnes TSX BT for maximum expansion and penetration. My sig has a 1:7 twist so for the most part, the heavier the bullet the better.

I know the gun is accurate. With standard 55gr XM193 i usually get 2-3" groups at 100 yards(not great), but with 75gr hornady TAP, i can get 1" groups all day with my Vortex 4x12x40 scope.

My question is about what powder i should use. I've got a 16 inch barrel, so wouldn't it make sense to use a fast burning powder? I need to get the maximum velocity/energy that i can. I've heard before that all the powder is burned before the bullet leaves the 16 inch barrel, but i'm not sure. Does anyone have any powder recommendations, or even better, some accurate load data with this gun?

Thanks!

 

[BCP]

Re: Trying to Build Accurate load for Sig 556

What kind of powder do you have on hand right now?

 

[AntlerAddict]

Re: Trying to Build Accurate load for Sig 556

I don't have any at the moment. My brother has a ton of reloading stuff and a fair amount of knowledge, so i'll be working with him. I just came from the sporting goods store and was a little overwhelmed by the whole rack of powders. I guess i'll probably just buy a reloading manual and go from there.

 

[Shady_Jay]

Re: Trying to Build Accurate load for Sig 556

heavier bullets do well with RL-15 and Varget

 

[AntlerAddict]

Re: Trying to Build Accurate load for Sig 556

Is that just from your personal experience or is there a certain characteristic that helps those do better with the bigger bullets? I know those two seem to be very popular, so i was just wondering.

 

[Shady_Jay]

Re: Trying to Build Accurate load for Sig 556

Personal experience. Anything less than 60gr I use ball powder.

 

[Grump]

Re: Trying to Build Accurate load for Sig 556

Top velocity almost always comes from the slower powders, if you can fit enough into the case.

Regardless of barrel length, IME. Check the reloading books and see whether I'm nuts on this.

It's just that the slower powders and resulting heavier (by weight) charges give slighly more recoil, and usually more blast and flash.

Your choice as to what you want to put up with.

 

[GunjunkieM24]

Re: Trying to Build Accurate load for Sig 556

I have used this load for a while and just ordered components for another 1K to reload. It is an absolute tac driver out of my 18 Inch MK12Mod1 with a 7 twist barrel.

LC Brass
24.0 grains of Varget ( please work your load up as this is a fairly hot load )
77 Grain SMK's
CCI #41 primers
Load to mag length
I am getting 2727 FPS on a hot day and they have performed exceptionally ( some 1/2 inch groups and sometimes better if I can do my part ). This load has exceeded any factory ammo I have used for accuracy including the MK262 and other offerings from Hornady and Black Hills.

Hope this helps.