I also second the suggestion of building a .45-70 on a 12 ga action as was done with my Beretta pictured below:

Note gas escape channels on the action face.
It is also nicely finished externally and is very effective with low power/pressure ammo. Also little recoil:

Or another American cartridge, the .405 WCF, another proven killer of big game than uses Hornady 300 grain ammo or hand loads from 210 to 400 grains.:

This made on a Simson Co Suhl 12 gauge action with wood by B Dudley.

I do not make guns, I just like them and hunt with them.

Edited by crs (11/29/19 09:03 AM)
Edit Reason: correction
NRA Patron, TSRA, Whittington Center, DWWC,DRSS
Reloading Ballistics App at http://www.xplat.net/