Reloading 300WinMag which powder?

[JNG]

I will soon be loading 200gr Sierra Matchkings for my 300WinMag rifle with a 27.5" barrel.

Which powder should I use?
H4831SC was recommended but it looks like I can get a little faster muzzle velocity from a few other popular choices.
IMR-7828
IMR-4350
H-1000
IMR-4831

What do you guys recommend?

 

[Gibbs505]

I am using H1000 and am going to try IMR7828. However I have gotten good accuracy out of H1000, 1.25" with no development! First three shots! I just have a bunch of 7828.

H1000 was developed speciffly for rounds like the 300 win mang and the weatherby. Before the 30-378.

 

[Johnn Peterson]

In my .308 Norma Mag, that I presently have, and in my .300wm that I have 'parted with, my powder of choice by far is IMR 4350.

 

[303carbine]

I believe any of the powders you have listed will work fine, 100 fps one way or the other doesn't matter.
Speed is fine...accuracy is final.....

 

[martinbns]

in mine reloder22 is tops.

 

[Griffoneur]

IMR 4350 gives me great accuracy.

 

[t-star]

i use 7828, but it's 338 mag- heavier bullets and slower powders

 

[Johnn Peterson]

I forgot to add, with the IMR 4350 I'm using a very close compareable bullet to what you're using, the Sierra 200gr SBT. The most accurate combo I've found in the .308 Norma & .300wm. They also work very well on Moose. I can't recall what charge I used to use in the .300wm but in my .308 Norma I went with the accuracy & hunting load listed in the Rifle & Handgun Reloading Data, Edition V manual. I have a target I shot @ 100 yds that 4 out of 5 are at 0.750". The 5th ended up opening up the group to 1". As luck would have it, for a test rifle for their loads they used exactly what I have, a Schultz & Larsen. No sense in 'reinventing the wheel' and the load has worked out well.

 

[cariboo_kid]

So it likes all the same powders the 270 uses, that's good to know.

 

[bisonhd]

RL22 seems good to me. I did try some leftover H1000 and got exceptional accuracy but never had the opportunity to get the velocity. I wouldn't get too hung up on +/- 100 fps.

 

[boney]

I've had good luck with Reloader-25 in my 7mm RemMag pushing heavy slugs.Should excell in the 300 aswell.

 

[Sir William]

I have used H1000, H4831 and RL22 with 180gr bullets. If I want something lighter to use at the range I load up 150gr with H4350. H1000 was first designed for bench rest shooters I believe, I always turn to it first.

 

[GunBoy]

Try Rutumbo Powder, I had nothing but GoodLuck with it, in 190BTHP, 220BTHP...

Gb