You are fine running small rifle primers in 357 brass in whatever platform you want to. The only issue might be if the primer cup on the small rifle primer is thicker or tougher than the pistol primers, and your firing pin spring is too weak. I don't think it is going to be an issue though, because CCI, for example, uses the exact same primers in their boxes labeled "CCI 400 Small Rifle Primer" and their boxes labeled "CCI 550 Small Pistol Magnum Primer". The exact same primers.
That is good to know. very informative post all round.
