With all due respect to Ken O'neil, Alliant powder company recommends standard primers with 2400 powder because magnum primers can cause sudden pressure spikes when nearing top end loads.FWIW
Also, in Handloader # 240 there are two articles by the same author [Brian Pearce] on loading the .357, and the loads he publishes are always pressure tested unless otherwise noted by him.
In my opinion 6" bbls. are an ideal balance between sight radius, balance and packability.
