I was told years ago by a reputable gunsmith that plastic hulls were actually thinner than the old paper hulls and made the transition from chamber to barrel easier, in most cases. If your plastic hulls show signs of tearing your forcing cones are very tight. I am of the mind not to alter chambers or forcing cones but also own two classic oldies that have been lengthened from 2 1/2" to 2 3/4".

This ain't a dress rehearsal , Don't Let the Old Man IN