With some low-cost reloaded ammo I've bought, I have started a period of practicing with the same ammo I am now keeping ready in my guns for home defense and for personal defense: 165 gr JHP. It seemed like a good idea to try to use the same ammo for practice and for actual defense.

How true do you think this is? I felt that having the exact same recoil and trajectory characteristics might be important. I'll try it for a few months and then see for I do on some other ammo such as the 180gr JHP I used to use.

I used to think if I used 180 gr FMJ for practice it would be OK to fire the 180 gr JHP for defense. What difference does it make?

FMJ is generally much cheaper than JHP, at least in factory new ammo.