Are these hard cast or swaged (soft lead) bullets? The soft lead will foul your bore if you push them much past 1,000 fps. I am loading Speer swaged SWC HP with 5 grains Power Pistol for 800 fps out of a 4" Model 64 or 5.8 grains for 940 (+P .38 Special load). Speer #14 shows Bullseye loads from 4.3 to 4.8 in .357 Mag.
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