Maybe "killin power" was the wrong words to use as you can certainly increase the explosiveness on critters of less stature buy increasing speed and using bullets less hardy. But the same things that creates explosive results on a prairie dog can be a detriment for larger critters. Kinda like using lightly constucted varmint bullets in a centerfire is not a good idea for deer hunting. The same can be said when you use too solid of a bullet like FMJ's on game, again not a good idea.
But for it's case size, lighter/smaller/lesser construction doesn't = bigger critters.
An 85g .243 slug is HALF the weight of a 170 30-30 bullet.
And YET which gun is a better 400 yard deer/antelope rifle cartridge?
Hint- it's damn sure not the 30-30.
Actual Terminal ballistics of a rifle round do NOT stop at some arbitrary bullet weight You "think" is too small. Lot's of other factors such as bullet shape and construction muzzle velocity come into play.
If your bullet weight theory were actually true, the dead 'yote lung shot with a 20g 17HMR game point at 120 yards(Shown half way down the Rimfire central thread below) would still be alive. And the 30-30 would be a more popular long range deer and antelope gun that the "puny" .243.
http://www.rimfirecentral.com/forums/showthread.php?t=370398&page=2
