My last chrono session with Win. Silvertip was out of my Colt Delta Elite, in May of 2006. High was 1295 fps., low was 1202 fps. So, alot of deviation. Average was 1234 fps. at 575 ft. lbs. Nope, its a bit, as in quite a bit more than what a .40 S&W can do with a 175 gr. slivertip.
Its what I carried my last 5 years on the road, before retirement. Oh, as for expansion, in test tank, it expands to .805", with some fragmentation.