Pure velocity doesn't translate into killing power either.
What matters is #1 shot placement and then energy downrange. The fast CCI Stinger at 1640 fps only has a 32 grain bullet and has 119 ft/lbs at 50 yds. Their velocitor LRHP with the 40 grain bullet will deliver 134 ft lbs at 50 yds.
When looking for an air rifle a .22 cal at the same velocity will deliver much more energy than a .177, averaging twice the pellet weight. Keep in mind when they post their impressive FPS numbers they'll be using light weight pellets.

