I've had a few Montana's.I don't recall that any were terrible accuracy wise,if they liked the ammo. One 7mm WSM sucked if you fed it Federal Premium.With handloads loaded to normal velocity(not the hyper souped up over pressure factory stuff), it shot fine.
One 257 Roberts was stupid accurate.A match shooter at the range thought it was nifty,but asked how it shot.I told him it will put three shots into 1/2-5/8" at 100 yards.
He smiled and said "Show me". So I sat down and put 3 into 5/8"
He still talks about that.Nice when you get "called" and a plan falls together.
IME nothing fancy is required; I don't hold the fore end down. My left hand is back under the butt stock controlling the rear bag....but I do put a soft towel under the receiver,and don't rest the rifle way out on the fore end. The front bag is back under the chamber.Light rifles will "bounce" off firm rests,and groups will go to hell.Controlling the bounce is key.
Very firm sand bags are a hostile environment for a light rifle.
I do tend to draw a light rifle like a Montana back a bit harder with my right hand.
