Originally Posted by
SMD
Your Marlin probably won't need much.
I'll add a 'ditto' to those who recommended a set of ghost rings or peeps. I also replace the typical bead front sight with a post that allows better vertical reference. After it wears in, you might seek a trigger job and a dehorning of the metal around the loading and ejection ports.
I currently run Federal 30-30C through mine. It's a 125 grain JHP designed for varmints, coyotes, and small deer. As such it's probably the factory round least likely to overpenetrate in a home defense setting. I live in a state (WA) where the AR is perfectly legal to own with standard capacity magazines. I also live in a part of the state where its use would probably not raise eyebrows. But I see the writing on the wall here in the Evergreen State and I keep my Marlin 336 as a PC alternative to a semi-auto, magazine-fed rifle should our legislature tamper with the status quo.
Good luck with your Marlin!