Now, the 175 grain bullet doesn't have that problem--if fired at 2600 fps, it will stay supersonic at 1000 yards. The key here is speed, and you're going to lose a bit of it with the shorter barrel.
The problem is that I have not seen a factory 175 gr match load that will get close to 2600 FPS out of a 20" barrel like savagest has. I would bet that the FGMM 175 gr SMK will be going closer to 2450 fps... At least, that is a 6 shot average when I was out with a friend who was shooting his Remington 700 SPS Tactical.
Depending on conditions, that puts the bullet close to going subsonic around the 1,000 yard mark...cutting it close to say the least