Re: H870 or H1000 Loads for 65x284 ?
In my experience with a few 6.5x284's, including the Savage LRH, is that H4831sc and Retumbo, using 140gr bullets will produce top accuracy, low ES, and excellent temperature stability. Using 24"+ barrels both powders will generate velocities in the 2900-3000+ FPS range with Retumbo having a 50-75FPS advantage over H4831sc, a slightly faster burning powder. Either standard or magnum primers will work with Retumbo powder but I have found ES and accuracy can be better with standard primers at the cost of 25-50 FPS. Retumbo is not too slow burning for the 6.5x284 case design in a 24/26" barrel, and generates lower pressures than H4831sc. H4831sc seems to produce best results with standard primers. I have tried H1000 but found velocity, ES, and pressures sub par compared to Retumbo and H4831sc.
"Let us speak courteously, deal fairly, and keep ourselves armed and ready"-T. Roosevelt