Originally Posted by
DougGuy
You won't hurt the gun with those loads. The harder the alloy, the more pressure it takes to push it through a smaller throat but it would take a LOT to make a load dangerous to shoot. It would have to be already overloaded, and the hard alloy/tight throats would just compound things but they alone wouldn't be the root cause of an over pressure event.
It serves no purpose to size larger than the throats, size to a slip fit with fingers is all that's needed. Providing the throats are just a tad bit larger than the groove.
Many 357 cylinders won't chamber a round loaded with .359" as SAAMI specs (and my own pin gages) designate chamber mouth diameter at .381" and I have reamed quite a few cylinders that wouldn't take a .381" pin all the way to the bottom, so .381" minus .359" = .022" left for 2x case wall thickness. R-P is the thinnest that I know of, WW is the thickest, Starline may be right at .011" I don't have one readily available for measuring.