No one is arguing the "on paper" advantage the larger bullet has. What causes contention is if paper advantage is outweighed by the real world advantage. In many opinions, 17-19rds of "damn near as good" trumps 7-9rds of "maybe just a little better." This decision must be made by each individual user, and each weapon considered as a total package.
I'll carry the extra magazines to keep the better feel in my hand.............fat & wide gripped pistols don't horn me up.
If I'm going to a war & feel the need for high volume sustained fire, I'll bring my M4 & a [bleep] of 30 round mags.
This thread is (was) centered around personal protection, as in everyday carry usage, maybe even concealed carry (TIC), so in actuality, size & conceal-ability is a consideration.
