54, No. I just bought a bdl magnum rifle, I am not sure of the caliber right now, and had it barreled up in .375 H & H.. I think, it will only accept two shells in the magazine plus one in the chamber.. It should accept 3 in the magazine, but I never really tried to find out why it would not.. I have a .300 Wea. I barreled up on a 700 and it will accept three rds. in the magazine no problem.. It is probably some minor deal that needs adjusted.. If you have a chance, try loading the magazine with 3 rds, and see if all is ok.. For my purposes, I seldom load more than three rounds in any bolt action.. Best of luck..
A 700 will hold 3 rounds down in the mag like any other belted case based off the H&H case.
If I wanted a 375 on a 700 I wouldn't build I'd just buy a XCR 2 and restock it how I liked.
