I bought some poly wads last week...they appear to be loaded in "red" chedite hulls.
In two of my hammer guns the primers were blowing. (Before you start blaming my guns).....Neither gun has ever did this with any other hull primer combination. In one of the guns I've shot 3 or 4 hundred of the clear chedite hulls with black powder without incident. In a third gun the Poly Wads worked fine.

I might give the RST's a try.