Re: 270 Winchester + 150 Gr. Sierra GameKing + Varget
I've checked all of my manuals and none have data for Varget and 150 gr. bullets. Varget is a medium burning powder. You're going to get high pressures with low velocity. 150 gr. bullets in a 270 Winchester needs slow burning powders.
The on line Hodgdon manual shows Varget in 130 and 140 gr. bullets.
The 140 gr. bullet data goes from 41.0 to a max of 43.7gr. with a max velocity of 2772 FPS. I would guess you would reach a maximum of about 42 grs. or so of Varget with a 150 gr,. bullet. You would have to start at about 40 grs. and work up to max. You just won't get efficient velocities. Powders in the 4350/4831 burning rate are much more efficient than Varget.
I've loaded for the 270 Winchester since the 1970's. I have used medium burning powders for 130 gr. bullets, but for normally use the slow powders for bullets 130 grs. and up.
I do see IMR 4064 and IMR 4895 being used for some of the heavier bullets in the Hodgdon on line data. IMR 4064 is close to Varget in burn speed.
As long as you start low (not more than 40 grs.) you could get Varget to work.
