Hello, this is my first post here and I'm seeking some guidance. I have two ARs I have built one is a 16inch 556 clambering. The second is a AR9 8 inch barrel. I have no operator background whatsoever just enjoy shooting, I have shot a lot of .223 and 9mm and I enjoy them both. Now where my question leads me is- let's talk about potential home defence and 100y and in SHTF and small/med size game hunting. Obviously a 223 has more power then a 9mm nobody will argue against that, but it seems like most people will choose 223 over 9mm for "stopping power". Now obviously 308 has more stopoing power then 223, still seems like 223 is the choice the majority of people will choose despite the 308 having more power then the 223. So with that being said what's the point of its not the best caliber but it is substantial enough to work effectively without being "overkill" say 50BMG. Let's talk home defence, say someone were to break into my home and I had to use either a 9mm ar pistol or my ar15 would they both work perfectly fine at those distances or would the 223 be superior every time regardless or the situation? I like the thought of my AR9 pistol as I can carry it in a backpack while traveling and really cheep ammo to train with and also a shorter package then a 16 inch barrel. But realistically say in an extreme situation a fight within 100y would a ar9 be outgunned by a ar15 of equal barrel length? I know the 223 had more power but is it enough power to realistically make a difference?