Standard Deviation

[gregrn43]

When y'all are working up loads for a hunt, what is the standard deviation that you look for? I'm working up a load for my 300 win. 180gr scirocco with H1000. With 80grs I have a std dev 10.4. Max velocity is 3102, min velocity 3072. Rifle is a Ruger M77 mark II 24 inch barrel. This SD was with a 5 shot group. The load shot pretty good, but I think I need to tweak my sitting depth a little. I cant extend it very much because it will not fit in my magazine. I shot 4 different loads and this is the best SD that I had.

 

[USMA84DAB]

10 shot group - Std Dev of 7.5 FPS - looking for 2650 FPS, 10 shot average was 2654 FPS. I called it good.

 

[samson7x]

I like it to be <10 but if it groups 0.5" at an SD of 14, I'm rolling with it.

 

[Surgeon1]

Real frankly I always strive for Std Dev less than 5 no matter the caliber, but sometimes it just isn't achievable. Specific to Swift Scirocco, I've used them in several 30 cal rifles and most of the magnum cases. Ditch the H1000 and go to RL17 or to 4350. The H1000 is to slow a powder in the 300WM in my opinion. Swift Scirocco and Std A-frames seam to work best at 2850 to 2950 IMHO.
I use the 200gr A-frames at 2850 on everything from elk, moose, and African plains game thru eland.
Save the H1000 for 300RUM. Also, most rifles in 300WM that I've worked up 180 Scirocco's for like
20-40 thousandth off the lands.
The load you have sounds surprisingly good for H1000 and it is very temp stable but when compressed loads it can do some weird things pressure wise. H4350 is about as temp stable as you can get. Unfortunately, RL17 isn't very temp stable, but in 300WM I've seen some of the best accuracy. I've also had pretty good luck with 4831SC and it meters well and is super stable.