Rifle primers are different height than pistol, as rifle cases have deeper primer pockets, so I'm told. I've never measured the difference, but 100 rifle primers vs. pistol, in a filler tube, they are obviously not the same. I have used small rifle primers in pistol cases, but they stick out a little more and may cause problems in a revolver, or especially in a semi-auto, when the slide picks up a round, it could cause an out of battery discharge, something you sure don't want! Also, their are differences in detonation duration, as rifle charges are usually larger and slower burning and the manufacturers have this down to a science. I agree, soak em. Safety is the primary concern in reloading. Don't mess with reloading information provided by powder manufacturers, they have access to expensive equipment for testing. Long post, but I have a Browning BLR in 243 and a Savage bolt action 16. Using the same load, the BLR blew the primer clear out of the case and extraction was extremely difficult. The Savage bolt had no problem with it. Needless to say, I only fired one in th BLR, the rest were delegated to the Savage. Live and learn!