I just couldn't get decent accuracy with H1000 and the 208 Amax in my rifle.
In other 300win mags that I've had H1000 was great. It is also great in my 7WSM.
But for some reason it did not work out in this rifle.
In fact I was slow to give up on it and wasted more time than I should have.
With Ramshot Magnum I got great accuracy with very little vertical at 565yds where I did my testing. In fact I shot a group with 77.5gr and 79.5 gr and all shots from both loads formed a 2.5" group with only about 1.5" vertical. That's pretty good considering the 2 gr difference.
I settled on 78.5gr and it shoots amazing to say the least.
I have found it very stable through a variety of temps, of course here in Tampa that is only from 40* to 100*.
I haven't used it in the sub zero temps up north. But at least I'm not getting pressure excursions in the high temps which is usually a concern.