H-4350 is faster and it's the 'go-to' powder in the 260 Rem.
I use H-4831sc in my 338LM loads and some 7RM loads. Actually, 4831sc is my #1 choice in the 338LM, shooting the 250s.
Face it, you can get just about any powder to work in any cartridge, if you spend enough time experimenting...