Some of you may find this info helpful. Today I ran several 357 mag factory loads through the chronograph. All were fired from my Ruger SP-101 4.2” 357 mag.
HSM Bear Load, 180 HArdcast - 3 shot Avg = 1100 fps
Doubletap 200grain Hardcast - 3 shot Avg = 1275 fps
Conditions were 30 degrees F and overcast, humidity 93%, pressure 30.2 inHG.
HSM claims 1200 FPS but I’m not sure what length barrel they use.
Doubletap claims 1200 FPS from a 4” barrel.
I’ll be testing the Underwood Xtreme penetrator and 180 Hardcast as soon as I get some.