Abstract: An extruded stick-type propellant grain is disclosed that includes a length separated from a strand of extruded propellant material having a predetermined cross-sectional shape provided with a predetermined number of spaced, radially distributed, hollow non-round longitudinal perforations formed in said length of propellant material parallel to and extending along the length thereof and separated and surrounded by a web of the propellant material. The perforations have a geometric cross section selected from the group consisting of non-round shapes that enhance uniformity in unburned web thickness during a normal burn of said length of extruded propellant thereby reducing the amount of unburned slivers. A central perforation is also provided.

Abstract: An extrusion die for use in producing perforated stick-type propellant includes a die blank having a central passage therethrough, the passage having a tapered entry, an open lattice webbing structure having struts in and spanning the central die passage, and an array of die pins for imparting perforations in material forced through the central passage, each pin having a fixed end attached to the lattice structure and a free end extending parallel to the passage beyond the lattice structure.