I have a 375, and to keep it tame ive been loading 69 gr of rl-15 under a 270gr nosler at about 2600fps+ which happens to be their starting load. Is this enough fps for most dangerous game?

Yes, but you might want to go to 300 grains at 2500 fps as it will do everything.

We used 270 gr. TSX 375 @ 2750 fps in tanzania this year. We shot from Impala to Buffalo with it and it did great Most likely will never use 300 gr again, if i want a heavier bullet I will use a heavier caliber.

I've had great success with a 270 gr TSX over 74 gr RL-15 and a Win Large Rifle primer. PH recommended Large Rifle vs LR Magnum primers in the heat and it has worked fine for plains game up to zebra and gemsbok with complete pass through in each case. Very accurate in my 375 H&H as well. Never chronographed but references suggest @2700 fps. Would not hesitate to use it on buff if that's what I had at the time; however, for buff I have used (and prefer) a bigger caliber like the 416 Rem Mag with North Forks soft point and cup point.