Assuming you are correct why would someone with a 357 Mag revolver be allowed to shoot moonclip 155 PF 38 Special +P ammo and someone with a 38 Special +P revolver not be allowed? Either gun can make the power factor and stay under their SAAMI pressure specification. A model 13 is identical to a Model 10 except the chamber reamer is run 0.135 deeper and the roll marks on barrel. Similar for some GP100 38 Specials +P identical in every way except chamber depth and roll marks.

As I have said before these rules about what is and is not a legal revolver cartridge are really poorly written. Suck it up and use 357 magnums or let me Shoot my 38S&W.