Having had 4 SSK 375JDJ barrels since the early 80's that I shot thousands if not ten of thousands of rounds through over the years I can assure you it is just about as much fun as you can have with a Contender (the close second IMO is a 17 Ackley Hornet).
African game and the 375JDJ? JD and his hunting cronies took something over a dozen elephants and I don't know how many cape buffs with it to test it on dangerous game in the early 80's when the 375JDJ came out. I still have an old SSK Newsletter JD sent me full of specs and pictures and stories about the 375JDJ in Africa. One is about a charging elephant stopped at less than 18 paces by a 300 gr solid with a frontal brain shot (bullet found in the neck about a foot behind the skull). Another a cape buff frontal heart shot at 45 yards with a 300 gr FMJ that penetrated 5 feet. Anything that will kill a cape buff with one shot will definately kill anything that walks the earth.
That said, I think most people that are afraid of the 375JDJ are those with no experience with it. I pushed mine pretty hard as a handcannon junkie and only shot 270, 285 and 300 grain bullets whether my dangerous game was elk, bear or prairie dogs, usually with a full dose of powder to push them. With Pachy Decelerator grips they were a pussy cat to me, and I probably shot as many if not more one-handed as two-handed. I often "plinked" with them like most folks would with a 22LR.
The 45-70? JD also gives the 45-70 the credit it derseves by saying it is in a class of its own and the best 150 yard sledgehammer for hunting available for the Contender. He used 500 gr solids for Africa's dangerous game and 400 gr for everything else. I wouldn't try to push a TC factory barrel as far as he will his premium barrels though. Loaded down it is also quite tame to shoot.
By definition, a handcannon is 35 caliber or larger (perJD), but with lots of them the bark is worse than the bite.
Probably worth about what you paid for it...
Larry