First off, I commend your choice of caliber for a Deer rifle. In my humble opinion you couldn't have chosen better. Even better when you handload, about every Big Game bullet ever made is available in 7mm.
I've done more experimenting with my .280 than any other rifle I own, always looking for that perfect combination of accuracy and terminal performance. I've shot both the 139 SSTs and Interbonds, both with good results, but I keep coming back to the 140 Barnes TSX. I just can't find a better bullet.
Try the SST, try the Interbond, try every 7mm bullet available. Just make sure you include the 140 TSX. With a little experimentation you'll find the correct powder charge and OAL for your rifle. Then I think your search will be over, especially after you shoot a couple Deer with it.
My rifle likes H-4831, R-19 and R-22. H-4831 gives me the highest velocity and good accuracy, R-19 is about the same, but 55.5 gr of R-22, although a little less velocity, about 2950 vs 3050-3100 with the other 2, produces near half minute accuracy. That's what I've settled on. This is from a 26" barrel.
Not intending to jump your thread, but as a fellow .280 shooter I have to urge you not to pass up trying the TSX.
By the way, my .280 is one of those "inaccurate" #1 Rugers.