Re: .284 winchester
I shoot a .284 Win in 1000yd BR and use 55grs of H4831SC with the Berger 168 VLD, oal is 3.185".
I have a 30" barrel and velocity is 2960 fps, I've gone up to 56grs and just over 3000fps but groups weren't as good.
I would start around 54grs and work up, should find something that works around there.
Wayne aka WAMBO