Well I have a matched pair of 1898 Geha Mauser 12 ga bolt shotguns but unfortunately only one bolt head, so I will have to mix and match. Is this single shot competition taking place? If so I'll bring one that I get shooting. I have to remove Bubba's 1/4" bolt through the cracked wrist and replace it with a dowel soaked in Acraglas after filling the crack and clamping it all together.
The choke is "Ever so Full" so I'll ream that out to Improved Cylinder. If you have not seen a 12 ga made from a 8x57 Mauser Army rifle, you will be impressed.
Mikey