I would suspect that it can be done if you don't mind being in the warm area. My 375 will do 2750 with a 21 inch barrel with 76 gr of Re 15. That is max in the Barnes manual. I am of the understanding that it is a bit on the warm side. I get some pressure signs at this load. My hunting load I backed off a grain. That puts me at about 2700 -2690. I can't imagine that any animal that you hit will know the difference in 2750 and 2800. Much of our discussion and endeavor is just a chasing of our tail.

You should be able to get it with a highly compressed load of H 4350. I got 2770+ f.p.s. using 81.5 gr of H 4350 and 300 gr. Sierra boattail bullets. Winchester brass, WLR primer, Remington 700 Classic rifle with 24 in. barrel.

83 gr. of H 4350 gave me 2811 to 2822 with a 270 gr Speer bullet. But I had loaded to 3.72" o.a.l., which may be too long to feed through the magazine.

These loads gave me good accuracy.

I get pretty darn close (2790 avg.) with 76gr. RL15 with Fed. 215's and Hornaday 270gr. RN in my M70 (classic) that has a 24 in. barrel. It seems just a bit hot (approx. 50 fps over fact. load) but it shoots well. I'm thinking of backing off half a grain or so to bring it into line with factory specs. just in case I ever need to shoot "store bought" ammo so my sights would be close.

I have a 26" barrel H&H and while I have not shot the 270X's I have shot several 260AB's and used the 270X reloading data for them. I loaded barnes max load for the 270's using R15 with the 260AB substituted which was a little warmer than I like but they were doing slighly over 3000fps. I also tried a half grain under max with H4895 and the 260AB's to get a average around 2875fps. If your looking for velocity I would try the R15 first. My gun shot the 4895 load quite a bit better than the R15 loads though.