Thread: 303 vs 12ga slugs

Thinking of leaving the nest for Lincoln uni next year and only have a 12ga to take with me as the rest of the thunder sticks are dad's. I'm thinking about getting a cheap rifle e.g 303 for big game hunting, or considering just putting slugs through the 12ga (NOT rifled). what's the accurate range of these two options dyou reckon, is it worth getting an old rifle too?