I've had various .25-20s since 1952 and I'd say your game aspirations are a bit optimistic. You CAN kill both pigs and deer with a .25-20. BUT there are many "buts" involved.
The deer I killed with mine were Columbian Blacktails in the thick coastal brush of Northern California. None weighed more than about 100# with the guts and blood out. Ranges were under 100 yards, 'way under in most cases.
Only one of them was running and I spent three hours looking for him in the manzanita/ticks/rattlers and only found him because some ravens couldn't keep their traps shut. Hit him back in the liver and he took his time bleeding out.
The only pig I shot was just under 180#s field dressed. Range was about 20 feet--I was trying to kill him before he killed our two dogs who were visegrip locked onto his leg and nose. It only took 11 shots (two were misses because I was trying to also miss my beagle....).
Old timers I knew who used .25-20s for subsistence hunting lived right with the animals they shot and ate. They could wait for a perfect shot because they knew they'd see the buck or pig manana if the shot wasn't great today. Most of us don't live like that any more. They could also REALLY SHOOT those quarter bores because that's all they'd ever shot. And they uniformly used 86gr LEAD bullets since the jacketed bullets were a little more expensive.
Of course we now have better bullets, if you handload, especially for a single shot or any rifle that doesn't have a tubular magazine (I use a Savage Model 23B bolt action and a Savage Model 219 Single shot and have used a Winchester Model 43 bolt and an 1885 Lowall single shot, and a '92 with a 24" round full magazine barrel.).
I'd keep the ranges more modest and the game less big, say coyotes, jackrabbits and snowshoe hares, and turkeys where legal. Fun enough and little risk of having the critter run off and end up as coyote chow....
Others may well have more optimistic ideas! BUT DO ENJOY YOUR CLASSIC! I love mine.
