It is important to note in addition to the above, that fiber wads and nitro cards be used only in straight wall hulls rather than tapered hulls. Fiber and cardboard don't have the same ability to expand from narrow to wider travelling down the hull as does a plastic gas seal. Cheddite paper and plastic, Fiocchi are among those with straight walls. The rule of thumb in going from plastic recipes to NC and fiber wads with the same hull and powder as used in the plastic wadded hull is to use 10-15% more powder to account for the inefficiency. However, if your thumb gets blown off, don't come to me.
The overriding rule of thumb is to have loads tested for pressure. . Gil
