USPSA open pistol shooters have been using small rifle primers in their .38 Super major power factor loads for decades with no problems. I personally have experimented extensively with many powders and primers for hot .38 Super with no danger signs or problems. The sole reason for using the small rifle primer in these loads is to minimize or prevent primer melt. Small pistol primers will melt around the firing pin and even stick to the FP tying up the gun.....small rifle primers prevent this.

I have made cartridges with identical components except for small pistol vs. small rifle primers. There is no significant difference in performance.
Small rifle primers simply have a harder cup.

If you're apprehensive about doing it then don't.

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Bob.
SWCA 1821