All firearms will show a preference for one or more brands and projectile weights. You will have to buy as many different types as you can afford and conduct a shoot off between them. Your weapon will let you know what it prefers.
All weapons exhibit a preference for one or more brands and projectile weights. You will have to buy as much as you can and shoot to get the answer for YOUR weapon.
If your barrel is marked .300 Savage then you can shoot .300 Savage ammunition by any manufacturer. I do not know of a "300 Savage Winchester Magnum".
Best to ask a gunsmith for assistance.
Best left to a professional gunsmith.
300-500m
What is the price range for a browning patient 300 magnum rifle?
50-300 usd
The M69 suffix identifies your 300 win mag as being a browning BAR that was made in 1969.
How value is Browning 300 Win Mag Semi Automatic
$300-900 depending on condition, which grade, and which model Browning,
50-300 usd
depends on the model