Nothing wrong with doing most of your practice with inexpensive FMJ or lead loads. But it's a good idea to make sure that the bullet weight and velocity of your practice round is a pretty close match to your carry ammo. This assures that your Point of Aim/Point of Impact and the "feel" of your practice ammo will pretty closely match those of your carry round.

Of course, you should always shoot enough of your preferred carry round to make sure that it's reliable in your pistol. How much is "enough" only you can determine.

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Pisgah