I don't own a .300 Savage, but always liked the cartridge. The .300 is a bit of an anomaly....according to a couple of handloading manuals and a couple magazine articles, it's one of the few rifle cartridges, perhaps the only one, that actually lives up to its published ballistics. Presently rated at 2630 fps with the 150 grain load, it will usually hit 2630 to 2650 fps in a 22" barrel, and closer to 2700 fps (its original load velocity) in a 24 incher. The 180 grain loads will also hit their advertised velocity.
I've read a few revisionist ignoramuses on the net who say the .300 Savage is little more than a slightly hotter .30-30. What a load of drek! I think a 400-odd fps gain is a huge leap beyond the .30-30. The same self-styled pundits will say that the .300 Savage failed in its bid to create a short-action .30-06-level cartridge because the .300 Savage doesn't get even close to the standard '06 velocity of 2900 fps. They are conveniently forgetting that when the Savage round was being developed in the late 1920's, the standard velocity for a .30-06 150 grain load was.....yup, 2700 fps. What a great acheivement for Savage! Failure indeed.....harrumph!
Once again, from my reading, all indications are that it is difficult to exceed the published (and actual) velocities of factory ammo by handloading due to the small case capacity, however one can get 165 grain loads nearly up to the same speed as factory 150's, which would be a great performance gain in itself. Enjoy your 99. I have one in .250 that I haven't taken a deer with........yet!