Get yourself a 444 Marlin barrel for that Contender. Great fun.
My best of the best use is a TC Contender I built long ago.
Custom Barrel in .223, 16 inch bull barrel, Burris LER 2-12X, Pachmyer Furniture, extra swivel stud on front w/ harris BR-S bipod. Use it as my EDC long range Yote and Sod Poodle tool.
Works well, is easy to put in my day pack that rides on the front seat and is minute of bunny at 400 yard accurate off the truck mirror.
My current “teach a lesson in recoil” tool is a Ruger No 1 Tropical rechambered to 460 Weatherby Mag..... :o)
That 444 Marlin has to hurt, I know the 45-70 does ...:o)
Stay safe !