Re: I am looking in to buying a 300 win mag, for SAMBAR Deer Hunting up to 800m.
I own a Browning A-Bolt Stainless Stalker (W/ BOSS brake) in .300 Win mag. It's an excellent rifle and very accurate with the adjustable BOSS muzzle system.
I recommend 200 0r 220 grain bullets. The Berger 230 gr. Hybrid Tactical bullets are the very best for retained velocity and energy, as well as being less affected by wind than the popular 180 gr. bullets.
As for a scope, my Bushnell ERS 3.5 - 21 X 50 mm objective is a great scope for the money. I like the H 59 reticle but many prefer the TREMOR reticle. I use a 20 MOA Picatinny rail and Vortex 34 mm rings.
"There are no comfortable packs, only packs that are less uncomfortable than others."