Yea, that's what they do.

Hornady's velocity numbers aren't very accurate for many of their XTP's

For example, I recall them listing the .357 158 gr bullet window as 750 - 1400 fps IIRC. That bullet doesn't even think about expanding until 1050 fps. 750 is just a lie.

The 9mm 147 gr XTP is excellent if pushed fast enough. As in 1100 fps and up. Great choice in .357 sig. Hornady's own .357 load will do 1175-1225 fps.

Heavy cloth prevents expansion more so than newer designs.