300H&H Magnum twist rate and loads?

[takedown kid]

I have a 1951 vintage Win.mod.70 in 300H&H Magnum in as new condition.What is the rifling twist-rate and what range of bullet weights and loads are ideal for performance and accuracy?
I have the same rifle(same year) that has been rechambered in 300 Weatherby Magnum- Same questions.
thanks T.D.K.

 

[Jim Watson]

Winchester .300 H&H Magnum rifling twist is 10" same as .30-06.
It will handle any usual .30 caliber bullet weight up to 220 grains, maybe heavier. I think it is better used to shoot the heavier bullets at reasonable velocity than blowing a 150 grain bullet out at high speed.
I would load it with a 180 grain controlled expansion bullet of one brand or another for hunting, a 190 to 210 grain match type for target shooting.

Same deal on the one rechambered to Weatherby, only more so because of the larger case volume.

Load data is in Lyman 47th edition (I don't know about the current 48th.) and in literature/websites for Alliant, Vihtavuori, Hodgdon, and IMR.
Probably others, you will not lack for load data.

 

[takedown kid]

Thanks, I have over 30 years experince in reloading, but not with these calibers.I can tell readily if load is questionable, just wanted some with experience to supply a few loads that have been good.
I have already observed with initial shooting that they prefer projectiles of at least 165 grains and seem better around 180 gr.

 

[Jim Watson]

Sorry I can't be of more help.
I, too, have been handloading for over 30 years, but never with any magnum rifle and have no tested data. I am a bit recoil sensitive and you could not run after me fast enough to give me a .300 magnum.