Has anyone looked at this design or experimented with any of them. It is a joint cartridge design concept of Byron Smalley (he retired from designing solid fuel rockets for the company that supplies the boosters for the space shuttles) and Mic Mcpherson. The design is based around the inside diameter of the case at the shoulder is twice the diameter of the bullet. The shoulder is shaped into a parabolic curve, the idea being that the primer blast is focussed by reflection (think of the filament of a headlight bulb as the focal point) into a spot just behind the bullet base delaying the onset of bullet movement from the case and improving combustion efficiency. From a theory point of view I like the concept and based on preliminary results for a 22SMC with similar case capacity to a 22-250 and a 6.5SMC with a similar case capacity to the 6.5/284 the idea shows promise.