I won't give you advice but I will tell you I use exclusively Federal Gold Medal small pistol Magnum primers in my pistol cartridges calling for small primers. This happened because I could not get standard Federal small pistol primers. Before doing lots of rounds using magnum primers, I made a sample batch and chronoed magnum vs my normal ammo. I use a high-end chrono indoors with infra-red light source. No measurable difference in the numbers. I have been using these magnum primers ever since. The loads are moderate.

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Bob.
SWCA 1821