Mikey pretty much beat me to the punch on this one. In any event, I know that for Hornady XTPs there are velocity parameters listed on the older gray boxes(not sure if they're on the red ones, haven't checked). IIRC, the velocity window for 240gr. XTPs is 900-1600 fps. Meaning that expansion can be expected to some to degree at least at impact velocities of 900 and the bullet "should" hold together at impacts as high as 1600. Contact different bullet manufacturers or visit their website to see if they list the velocities that they reccomend for optimum performance. I use 240gr. XTPs and they worked very well on the ONE deer that I killed with it. I have no more experience to offer than that but like Mikey said, shot placement is the most important. I figure there are many bullets out there that'll give satisfactory performance on game.