Nothing custom at all on our waterfowl guns. Bone stock Browning Silver 12 ga., mine is camo and the boy's is black. Both are 3 1/2", although the only time we use 3 1/2" is when we intentionally go after swans. Federal premium 3" #2 is all we use from the start of season right down to the end. Works great on decoyed birds of any size through a modified Invector Plus. Give me high quality ammo that patterns well through my shotgun over any modification every time.