Wet Willie said:Poly wads: tried some shot cups in my 20ga, left a residue in the bore very hard to clean.
Also tried over-powder wads cut from ice-cream pail lids in both pistol and rifle. All left a residue that seemed like smeared plastic in the bore.
I'd say don't use poly wads in BP.
All plastic is not the same. The plastic in an ice cream bucket is not the same plastic as the frame of a Glock pistol. Plastic shotgun wads are not meant for blackpowder and those plastic wads will leave residue if fired with blackpowder. The plastic of the polycups is designed to withstand the blackpowder just like the plastic sabots we are not allowed to talk about but which are fired by the millions with no problems. I agree that they are needlessly expensive but they do have a purpose. They are specifically for use with Hornady's "hardball" for people who want deeper penetration than they get with soft lead. Not for plinking or target shooting but if you want more penetration from your .50 caliber a package of those Hornady hardballs may be a relatively cheap and easy fix.