Re: which caliber would you use?
E-mail Doug Miceli as he was the first to put the 338 Norma in a handgun. I think that he has a 23" barrel on this handgun though and it has been several months since I spoke to him, I think he is getting under the 338 Edge velocities with the longer barrel.
338X375 Ruger is a good round, basically duplicating the 340 Weatherby.
I was shooting the Edge yesterday and to date none of the above equals the Edge at any range and I still would not go another route. 338 Campfire/338X375 Ruger is an exciting round every way you look at it.