I love my Weatherby Accumark, with Night Force scope.
I shoot a Weatherby Accumark in .338/378. At 1000 yards it still has more energy and velocity than most guns have at the muzzle. So to utalize the capability of your cartridge you need a good scope. I topped mine with a 3.5-15X50 Night Force. No other scope even come close in my book. Any larger than 15 power, your heart beat will interfere with your settling on your shot. Each heart beat will cause the scope crosshairs to swing right, then back left, then come back to center. I even notice it at 15 power, but am able to time it so I make the shot when the crosshairs come back to center.
Now for mounting the scope. After ripping the lug off a set of Lupold Rings, then I had the original screws for the base plate sheared off. Got a custom Base Plate with larger screws, that worked. Then I found out Warne Rings could not hold the scope from sliding under recoil. I finally called Weatherby and they put me in touch with a guy that makes a Picatinny Rail and matching rinds just for Weatherby Accumarks. It was a bit spendy but I am totally satisfied with the results. I did not get the picatinny rail just the rings.
I am shooting a 225gr Nosler Accubond in front of IMR 7828, at 3210fps. I can not remember the load off the top of my head. When I get back home in March I can give you my loading data. So far I've dropped a Moose at 810 yards with one shot. I killed a Grizzly at 620 yards. First shot complete pass through right behind the shoulders. Took out both lungs and nicked the heart. Bear turned and started running towards the spruce trees. Second shot hit the spine, just behind the shoulders. Bear rolled behind a bush. Then I saw the bear standing on it's front legs looking around, I could not see the rear. I put a third shot through the neck dropping it instantly.
I am currently hitting a gallon milk jug at 1000 yards. At 1200 yards the jug has a 50/50 chance of surviving. I'm still working for 1200 yards.