RE: ideal rifle
My all round rifle is a 375H&H but that’s mostly just fun, if I was to have any gun for the job it would be a Remington 870 with both a rifled and smooth bore barrel.
A 30/06 is another top option for most game.
For pigs I use a SXS 12ga and buckshot or a 1 O/Z lee slug or my 260rem and a 120gr pill.