Regarding glass, I put a 42mm BSA red dot on my Ithaca, which is a very hard kicking gun. It has enough recoil to torque out of my hands shooting at the bench off bags. Of course I figured that the BSA, in a B-square saddle mount, would be destroyed in short order or unable to hold a zero. Would you believe that it has been on that shotgun for over 5 years now, and has been re-zeroed exactly twice in that time? The red dot is perfect for a slug gun.
For the low investment, a cheap red dot and a "house brand" slug gun are a very deadly combination.
