RE: help me pick a slug gun
Most guys don't even get 1-2" groups shooting Centerfires, I see mostly 3-5"groups from slugguns at my club and most of these guys are shooting 870's and 500's with rifled barrels. I was able to get 5" groups at 100 yrds with a rifled choke tube using an 870. JC is certainly opinionated, I won't argue with that, but he knows his stuff and can prove it. I still have yet to see a sabot gun that is more accurate than the H&R except for the oes I mentioned earlier.
I will admit that my H&R is more accurate than most H&R's but every sabot gun is different even from the same manufacturer. You are correct about finding the right load for any gun but I have yet to see a sabot gun perform like the H&R straight out of the box. I don't buy cheap guns or scopes, I have a leupold vx-III 3.5x10 on mine and that helps the accuracy quite a bit.