Not being a reloader, I only shoot my .45-70 a couple or three boxes of ammo a year. The BB and Garrett ammo is beginning to break me. I was just wondering about moving up to the .450 Marlin. Anyone have any suggestions on this round? Any info would be appreciated.
I hate to talk anyone out of getting another rifle, but I would recommend that you take the money that you would have used on a new 450, and get set up to reload instead. 45-70 brass has a greater internal capacity than .450 Marlin cases, so a careful reloader with a strong gun can get more power out of the 45-70. Not much more, but it's there.
If you also give bullet casting some attention, you can make your own premium ammo for next to nothing. If you're always buying Garrett and Buffalo Bore ammo, a reloading set up will pay for itself in no time flat. Tinkering with loads and casting bullets can be a great deal of fun, just in itself.
That being said, the .450 was invented with folks just like you in mind. It offers similar performance to semi-custom/handloaded 45-70 ammo, but it offers it to the non-reloader. .450 ammo still has to be ordered in my neck of the woods, so it doesn't offer any advantage as far as being more available than Garrett or BB. Since you've already found high-performance 45-70 ammo that you like, and you seem to want to stick with factory fodder, I still can't come up with any real good reasons for a new rifle, other than it's always fun to get a new rifle. :grin: