IIRC these Siamese Mausers are in the same class as a Ruger #1.
Your shoulder will give out before the action will!
A hot 45-70 load will give you all a sane person would want with smokeless powder. Try the Hornady 350 gr Interlock.
whelennut

I like to do my hunting BEFORE I pull the trigger!
There is only one kind of dead, but there are many different kinds of wounded.