How many practice sessions will it take to hit a perfect target from 10-15 feet away and what kind of gun would you recommend?

I use a 40 cal beretta px4 storm and have no issues hitting perfect center

Are you looking for a concealed firearm? A rifle to hunt or target practice? Or self defense? For a target in that amount of feet i would recommend a 9 millimeter, if a rifle then i would recommend a AR15.

It depends on hand and eye coordination. I prefer a rifle like a 10-22 Ruger. Cheap and cheap to shoot