357 magnum primers

DRONE, if memory serves, the originators of the .357 Magnum round used small rifle primers almost exclusively through the round's development. I believe this was because the had to resort to using rifle powders intended for small-case rounds, to obtain desired velocities. The rifle primers not only assured more thorough ignition, but its thicker cup also added an extra safety margin against piercing from high pressures (so high, that they exceed current modern limits).
I, too, use small rifle primers EXCLUSIVELY in my "heavy" .38 Super reloads, and will use them when making hunting/defense-level loads for my .357 Magnum revolvers. Because the propellants I use in both calibers are easily ignited by small pistol primers, the use of small rifle primers is strictly a concession to safety on my part.

As has already been recommended (probably), If you are not starting with a minimum load, go back to minimum and work up in 0.1-0.2 gr. increments, so that if the hotter primer is jacking up pressures, you'll see it coming before it does any real damage. THIS is where a chronograph comes in VERY handy, to detect disproportionate velocity increases, or velocity
"plateauing", which are both excellent indicators that reducing the charge is desirable.
MY experience with "reading primers" to determine if excessive pressures are reached is that this is more difficult to devine from SRPs than SPPs due to the former's thicker cup. When the SPP on a reload is more flattened/cratered/ punctured than on a factory load, it is likely that you are at or above SAAMI MAX pressure with that load. If a SP primer with a thicker cup is substituted, the deformation will be lessened, despite the high pressure. This makes it difficult to decide what's happening, pressure-wise.