I loaded 56 grains of H4831 behind the 168berger in my 280rem with 24" barrel and got 2750.
I'm not sure what the go-to powders are for the 7rem mag but if all you're getting with Retumbo or H1000 is 2800, you need to go to a faster powder like H4831. I would want a 7mag to send the 168s at darn near 3000.
I'm not gonna shoot here. I'm gonna shoot waaaaaaaay over there!