9mm or 45.. ok, but..
...
I was shooting my Colt Defender 45 one day, and a young man (great shot) asked me if my gun was a Defender model. I said yes, and asked him if he'd like to shoot 2 mags worth with it. He smiled and said thanks, and asked me if I wanted to shoot his sub-compact HK (IIRC) very small 45.
We exchanged guns, and he shot the Defender like a tack driver, and I was very surprised at how well, and not a difficult "recoil" issue IMO, his little 45 was.
His had a double stack mag, making for 10 shots, IIRC, but I was impressed as the grip, small, but did have a little pinky slot on the flush bottom mag, did not feel that thick, but I knew something was up when I fired the 8th round, thru the 10th.
Then I asked him if he'd like to try my Beretta Px4 40cal, and it took him for a good ride the first 20 rounds.. lol, then he found the grip, and the last 10 rounds were nicely grouped.
Moral of the story: IMHO, if one wants to get a sub-compact, either get a 9mm or a 45cal, as the 40cal is gonna be the least forgiving, and the longest ride, for one to get the feel and accuracy with, especially in quick followup shots.
LS