Lance, the Sig Sauer Romeo-MSR/Juliet3 is up to the task. budsgunshop.com/product_info.php/products_id/714024705/sig+romeo+msr+rd+mgnfr+combo+kit ------------ It is rated for better than 12ga recoil and a good review of durability is here : https://gunmagwarehouse.com/blog/sig-romeo-msr-tortured-fried-frozen-and-shot/

Lance, personally for a Marlin 45-70 I'd use a lpvo scope. You can get them with 1-4 magnification, 1-6, 1-8 and some even go up to 1-10 magnification. If interested here's a link to a Leupold 1-4 lpvo scope............... budsgunshop.com/product_info.php/products_id/47159/leu+freedom+1.5-4x20+matte+pig+plex............... As for a red dot/magnifier I agree with James and Edward you'd have a hard time beating the Romeo and Juliet combo. Here's a link to one if interested................... budsgunshop.com/product_info.php/products_id/714024705/sig+romeo+msr+rd+mgnfr+combo+kit................. Hope this helps.