You will find there is very little variation in the primer pockets in brass. Certain brands will be a couple thousandths deeper than others. It is seldom any problem. Uniformity is more important to accuracy. As scrapper said, seat all primers so they are fully seated, the anvil inside snug against pocket seat. You want no movement of the primer possible when you strike it.

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H Richard
SWCA1967 SWHF244