JDP_12 "Welcome to the Forum."
As an instructor I take exception to your suggestion of only shooting & practicing with the exact ammo you use as carry ammo.
You mentioned it about about it being great shooting an economic caliber to build all the good shooting principals. With that I fully agree.
But it has been documented, proven, & well known that in a stressful,, combat or self defense situtation,, MOST people,, unless they are combat veterans, (soldiers using the skills daily,) will NOT notice recoil, count shots, focus on the front sight, etc at all. They get tunnel vision, tune out sound,, and the adreniline causes them to focus on the threat alone.
So,, practicing with cheaper ammo, to become "muscle memory" familiar with any SD firearm is an EXCELLENT thing. You can occasionally use the full power SD loads, to understand & learn the differences in them vs practice ammo,, but it's not as necessary to practice with them exclusivily.
A highly respected police LEO instructor, author, & court paid expert Mass Ayoob & I were recently discussing several things,, and a few casual comments about this subject were made. He agreed with me completely,, and he makes it known in his books & classes.
The human body responds to training,, especially repetitive identical types of actions to where it becomes "muscle memory." ingrained into our subconciousness. Think about driving your car. You do all the same things each & every time you get in a car,, and do not think about each step performed. It has become muscle memory to unlock the door, open the door, get in, put on the seat belt, insert the key, placeing your foot on the brake, checking your movement area, placing it in gear, using the gas pedal & brake, & actually driving. Muscle memory.
Same thing with shooting.
I'd rather have a person who rarely shoots a gun shooting at me with their big 45's vs a person who also has a 45 but practices with an identical 22 a lot. The one who practices a lot will most likely hit me,,,using muscle memory.
So,, again,, I agree with Sam in that spend the time, efforts & money in cheaper practice ammo, and become muscle memory proficient with the same gun,,,!