I wish I had a suitable answer for you, amigo! I simply can’t relate to the statement, “I don’t want to buy another ______ rifle.” Personally, I’d want both a 450B bolt gun and a Marlin 1895 45-70 - AND a 450/458 AR, and a whole bunch more.
So here are some musings among the two, some of which might resonate for you in your decision making process, or might not...
• The bolt gun is likely going to be more accurate.
• The Levergun is an opportunity to share in a dying tradition, and further, share that tradition forward to others of the next generation.
• Replacing a Marlin 1895 45-70 in the future will be more difficult. Right now, it’s looking like replacing a bolt gun in 450B is going to get easier. Might not quite really be an independent bullet point, but something to also consider.
• The Marlin can be loaded to considerably higher performance than the 450B.
• Ammunition, in this generation, seems to be more widely available with more varied options for the 45-70 than the 450. Brass is the same.
• The Ruger and Mossberg bolt guns have detachable mags, easier to empty and reload than the levergun.
• 450 uses .452” bullets, which means cheap revolver bullets can be used for plinking, but alternatively, it also means there aren’t quite as many suitable hunting bullets available. The .45-70 is straight up, all .458” rifle bullets, with a lot of bullets designed to expand in its velocity window.
• If a guy is so interested, a 450B bolt gun can share ammo (and mags, depending upon model) with an AR. The 45-70, not so much.
• Optics are more readily acceptable - for whatever silly reason - to many folks on a bolt gun than on a levergun. I use optics on everything, but some folks whine.
Personally, my MO is to save up for another rifle, and then another. I don’t have a .450B bolt gun, but have to acknowledge I’m tempted by one. I do have a couple 1895 45-70’s and a 458 Soc AR - if I were motivated by otherwise irreparable circumstances, I’d sell the AR before the Marlins, despite losing money on the AR’s, but potentially profiting on the 1895’s.