My only HP experience before now was with an Ideal 358439 back in the '60s & I never gave those any kind of test.
The 359 Hammer is my 1st. MP HP mold. My test load was the wide HP with 4.6 gr. HP-38 in .38 spec. case with a Federal #100 primer. the alloy is 50/50 COWW/SOWW+ a guessed 1.5-2.0% tin. After reading about the alloy some members are using I was afraid my alloy might be too hard (brittle).
I have been saving empty gallon milk jugs: I used 7 since I had no idea about penetration. The boolit stopped in #3.
The photo tells the tale: I'm pleased. I think I'll try the penta point with GC in .357 cases next (with something less than a maximum load).
Also on future test I'll not stand so close to the jugs in order to stay dry.
Henry