I prefer bigger bullets, but I continually read comments about how there is little difference in the actual effect of modern HP ammunition between 9mm, 357 Sig, 40, and 45. I can easily understand how a millimeter or two of diameter is not as important as an inch or two of exact shot placement. Given the understanding that shot placement trumps caliber and follow up shots may be required, accuracy and speed of follow up shots are both important. Since we are not going to count on a one shot stop and could be faced with more than one assailant, a 6 + 1 or 7 + 1 capacity is unfavorable; I am including capacity as a factor in my choice of carry pistol. Using my Glocks, I decided to obtain some fresh data with carry ammo. First, I fired each 8 10 shots slow fire at 7 yards to make sure the horizontal adjustment was good, if needed I tweaked it. I prefer to aim right on that small red dot and have the bullet POI either right on or up to about 1 high. Satisfied with POI, next was double taps. My emphasis is on 1st 2nd shot follow up time. I want both the first and 2nd shot to hit a 6 circle. I put several 6 circles on a larger target at 7 yards. I had not used the shot timer in about a year, so I gave myself a couple of warm-up runs with the Glock 19 prior to data collection. This is the method I used for my data; I would shoot 4 pairs (8 shots) then check to see if any shots missed the circle, after covering any misses I repeated with 4 additional pairs. In order to obtain what I considered to be a fair representation of performance, I eliminated the greatest (slowest) time from each of the four pairs; if a shot missed then I also eliminated the quickest time. The result was at least 4 pairs that remained (for each pistol) and they got averaged. I use the flush fitting magazines in the 30SF but all subcompacts (26, 27, 33) have Pearce +0 bases. All of the pistols have Meprolight night sights except the 33 which has XS Big Dots. Results: Glock 19 using Federal 124 gr. HST +P: average .26 sec with 13/16 hits. Glock 32 using Winchester Ranger T 125: average .26 sec with 13/16 hits. Glock 23 using Remington Golden Saber 165: average .27 sec with 13/16 hits. Glock 30 SF using Federal 230 gr. Hydra-Shok: average .28 sec with 13/16 hits. Glock 27 using Federal 180 JHP*: average .29 sec with 15/16 hits* *I was skeptical with this result and Federal 180 JHP is not my carry ammo so I ran it again. Glock 27 using Federal 180 gr. Hydra Shok: average .30 sec with 14/16 hits. Glock 26 using Federal 124 gr. HST +P: average .30 sec with 15/16 hits. Glock 33 using Winchester Ranger T 125: average .35 sec with 13/16 hits. I was most pleased with the total cumulative POI from the 19, 23, 26 and 27. I did not include my 29 SF in the test, because when I shot the initial 8 rounds slow fire to check POI it was higher than I prefer, even with light 155 gr. ammo and recoil was noticeably stiffer than the others. Conclusion: Take what you want from this, but I am surprised by the slight to non-existent difference in follow up times (9mm vs 40) with similar pistols and hits on target.