If I did not have a weapon that might suffice in this category, I would consider this: http://www.excelarms.com/handguns/xseriespistol.html in .30 Carbine.

Magazines and ammo are available and plentiful to stock up on. It could be concealled on a shoulder strap, capable of taking game, fairly high capacity, fairly quick reloads and ammo is pretty compact for transport.

If Kel-Tec would ever release the RMR-30, and it works as advertised, I would probably put it in first place over the Excel.