Here is some data I obtained using my Glocks:
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 shot 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 (speed without accuracy is penalized). The result was at least 4 pairs that remained (for each pistol) and they got averaged.
The subcompacts (26, 27, 33) have Pearce +0 bases.
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 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.
All of the pistols have Meprolight night sights except the 33 which has XS Big Dots and I think this negatively impaired its time.
As you can see, I was able to double tap the 32 just as quickly and accurately as the 19 or 23.
The 33 was a whole 5/100

(five hundredths) of a second slower and had one less hit in the 6'' circle, but it had different sights.