Well maybe I'm wrong but, from everything I've ever heard or read, the reason why they put a faster twist in pistol barrels was to impart the required spin of the projectile albeit bullet or ball as it was only traveling a short distance before leaving the barrel.

It made sense to me because otherwise you may as well have a smoothbore if the bullet/ball is only going to begin to turn with a slow twist before exiting the barrel.

Just my .02!

BPS