Folks,

excellent feedback, certainly threw up a couple of options I hadn't considered.
The 22Hornet option is not something I'd consider. The cart is just too small for what the action was originally designed. I already have two Martini Cadets chambered for Hornets - a 22 K-Hornet and a 17 Ackley Hornet.

I have a 45-70 in the safe so not looking at that as an option. Have a Lee Speed project in the mill now, a 375 NE 2.5" Flanged, so that will cover the 375 options.

I would think anything in the 40 to 50cal range being the ideal target calibre. I agree with you Daryl, the final choice has to be readily supported with brass, dies and projectiles. I'm having enough issues as it is with sourcing brass for my Lee Speed here in Australia.

Not worried about jacketed projectiles, more than happy with shooting cast. May even consider having a go at casting my own in due course. Velocity isn't a primary issue either as anything hit with a soddin' big lump of lead is gonna have a bad day!!

The end result would see use on the occasional pig hunt, with options for anything else as the opportunity presents.

Keep the ideas coming gents.