Yes Sir, Varget is the only powder I used to build loads in my 400 H&H, it's a model 70 classic that began life as a 300 WBY.
I use Quality cartridge proper head stamped brass FL sized the first time, neck size once fired brass to only bump shoulder back 0.002"
400gr Swift A Frames, 400gr Alaska Bullet Works bonded Kodiaks, and a bullet that will compare nicely with your long 400gr Northforks, the excellent 400gr CEB BBW #13 Safari solid.
All bullets sit over 77grs Varget, I had Lee Precision make a custom factory crimp die, iirc 115 bucks, the soft points get a good pinching in their crimp grooves, the solid gets a good pinch seated with the top drive band flush with case mouth, no bullets have ever moved after crimp, even battering in the mag box, they all stay put.
Fed 215 primers
All loads run 2409 to 2415 fps, a great great heavy medium bore cartridge, took it on a Tanzanian safari as my light rifle, shot plains game with it out to 288 yards using a 1.5-5 Leupold in Talley QD rings with levers, a Gold Medal Waterbuck at 228 yards off sticks in the river reeds was no problem at all, 577 Nitro double did the heavy lifting on Buffalo and Hippo on the ground at 18 and 21 yards.
The 400gr A Frame slapped a Leopard out of a tree that landed with a deadfall thud on the riverbank at 77 yards from the blind, so yes Sir, very versatile useful cartridge that really hits hard, I wont go into the details of the 400gr BBW #13 solid testing I did after cameras and video were put away, will simply say PHENOMENAL penetration!
Those two Northforks will serve you very well.
