Never shot the 45/70 but had a Marlin lever .444 for a long time and it was powerful and fun to shoot when I was younger, I would not shoot it now. Back then a standard round was about 260-265 gr jacketed bullet pushed about 2400fps and it's only .44 Mag caliber of .429, whereas your 45/70 pushes up to a 600 gr .458 diameter bullet at about 2000fps and 3600 ft pounds of energy(muzzle) vs 3000ft pounds for the .444.
I wish I had an older model. My 2012, JD 5055E has been a nightmare. One thing after another.That is what I always liked about the old 2 cylinder John Deere tractors. They were governed right at their torque peak. While other tractors would lug down somewhat under a heavy load the John Deere would just bark louder and keep going. The funny thing was that all the tractors back then would rev at about the same speed. But to my knowledge the John Deere alone ran at its torque peak.
I think I might sell it. At my age, I'm afraid to shoot it. Last time I did was a couple of years ago. No matter how careful I am with it, 5 shots will give the shooter a sore shoulder. I do think it would be great for home defense...
What is really going on is this. The tractor companies convinced the farmers that they needed tractors that leveled their land. The tractor would tell the farmer when it is time to service. Do lots of thinking for the farmer.Is it the case where only John Deere can repair it? They've been getting a lot of bad press in that regard.