I really enjoy double barrel slug shooting and hunting. I encourage you on this endeavor. They are great to carry.
For factory ammo, my double barrel smooth bore slug gun likes Brenneke slugs especially the Black Magics best. I have cylinder cylinder bores. But it flings almost all slugs I've shot from her (and I've tried alot) to pie plate accuracy to 50 yards standing. The Brenneke's I can get clover leafs! I just hate using those big badBrennekes on deer.
I would not worry about shooting magnums or high velocity slugs. For deer I find those high velocity and magnum slugs are way overkill; they just ruin meat.
I'd look into loading yoru own slugs, too. I am into that. I haven't loaded any ina while but my next session I was going to load up some patched .715 round balls. And in several powder ranges. Loading slugs is easy. I inted to hunt deer with mine this year again and will use round balls as soon as I find the most accurate recipe
I have a rear v sight on mine.
It is a hoot to shoot. Because of the light weight, though, I did find I really preferred adding an aftermarket Pachmayr Decelerator pad and a mechanical recolil reducer in the stock. It didn't affect the balance too badly and it really took the whack out of the sharp recoil I originally felt with this short 23 inch barreled and light gun.
