I've shot several deer each with a 9, 40 and 45 acp. I noticed a significantly quicker kills and penetration on deer with the 45 than the 9 and 40. I have read lots of articles saying that for law enforcement the 9 is just as good at stopping a threat. FBI has even gone back to the 9mm but I just don't buy it. But other than a handful of deer with each I really don't have much to disprove that theory. who buys into the 9 being as good or better for duty carry or hunting for that matter.
without a doubt, the 9mm is my number one favorite handgun cartridge to shoot, train with, etc. and for these it simply cannot be bettered...
for over 30 years i've tested many different handgun pills, with the more specific emphasis on the self defense handgun pills and cartridges. because these handgun velocities are so deplorably low, any hope of 100% consistent expansion is a "potential gamble", and with this being the case, it's best to figure you may "end" with what you "start" with--
the constants of weight and diameter. more of both in the bank is always better.
(in fairness, modern pills such as the Gold Dot and Federal HST are significant engineering improvements upon pills of yesteryear. therefore, each person should be persuaded in their own mind with regard to the variable in the equation concerning the potential gamble of 100% consistent expansion--ie., some pills begin/complete expansion on one side only, some "cave inward", etc).
whether it's a feral dog on the trail, or a goblin in the night--it's important to consider your decision based upon this one thing:
you're going to bet your life at arm's length. 
