.45-70 is great. I’ve wondered before how it works out of those short “guide gun” barrels. My .45-70 is a trapdoor springfield repro. SUPER fun to shoot with home-made black powder ammo.
Anyway, if it’s the gun you want, then go for it. 1000 rounds of ammo is certainly a big incentive. Even just 1000 brass has value.
Works great out of the guide gun...wish I still had mine.