In order to help keep recoil under control, I was thinking of using "reduced recoil" 00 buck, or a smaller shot...  What's the smallest someone would want to go on the shot size, while still retaining enough energy and velocity to still be effective on a man sized target at around 30-40 yards?

Or would 00 be the bare minimum?

Oh BTW, I'm talking about 12ga.

For reduced recoil, you are generally limited to 00 and 4 buck (in tactical loads)

You may want to pattern buckshot at 30 and 40 yards.  Buckshot really has a very limited range, inside of 5 yards you may as well be shooting a slug, past 20 or so yards, depending on each individual gun, you really should be shooting slug.  Just a consideration.  

Thanks,

I will pattern it at multiple ranges (Every 5 yards from 5-40), and see how well 00 and #4 works for me. Once I find what the maximum range is for each, I will start testing for penetration.

Steve

The reduced recoil loads tend to shoot somewhat tighter patterns in most guns, especially the Federal "Tactical" loads, due to harder (4% antimony) shot which is also plated. Larger pellets tend to hold somewhat tighter patterns than smaller ones, so tend to do better at longer ranges. 30yd.+ is probably not realistic if you have a standard gun and want to keep all pellets on a man-size target, but if you are not worried about your background, #00 and #000 can be relatively effective even at 100yd...IF they strike the target.

Me, I use #000, (yes, Federal makes a #000 Tactical load) as I have found it to be the best for my situation and in my guns. I do not like going lighter than #1 Buck, but #4 Buck can be very effective inside a house / building on soft targets.

I'm not fond of #4 buck. I try not to go any smaller than #1. You can find it if you look hard enough.

Thank you for your help.