What mag primer did you use?
The Winchester Large Pistol is also magnum primer, Winchester only makes 1 large pistol primer, and it can be used in both.
I use Winchester WLP for this reason, because I load 45 ACP witch needs regular primers, and also 44 mag witch in most loads it needs a mag primer.

I went back and read your post again, I see you used Wolf Mag primers for your test.

Again Winchester WLP primers are for mag loads.
I really don't think going to a mag primer with a starting load is going to hurt anything anyway.
Just watch for pressure signs.

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John