According to this guy's test out of an 8.5" barrel SBR with 1050 FPS MV, the velocity at zero feet altitude and sight-in and 59°F is 991 FPS, and the impact velocity at 100Y is 991 FPS.
Great video,
Where did you find that information? I tried to find it on there website.They work down to 600f/s
Thanks
Buck