I don't recall what you 're shooting but IC will produce wads like that generally a true cylinder bore will not. And not all shotgun barrels are created equal no matter what 's stamped on the barrel. An old brake cylinder hone on a cut-off barrel woked pretty well for me on one gun and a wide open poly choke on another put 3 in a paper plate at 125 yds. Lots and lots of variables, not the least of which is what 10,000 lbs pressure does to soft plastic. Also I found that 1 - 20 ga then 1 - 16 ga wad did better. The 20 is just a bit smaller than the base of my slugs and the 16 on top (it won't fit in the base of the wad) centered the slug perfectly.