C.W. Richter
AH legend
Most of the monometal bullets have to have the grooves cut in 'em, as they're longer (otherwise, they'd have even more surface area in-contact with the rifling than shorter, more dense jacketed bullets, resulting in greater pressures, undesirable heat, necessitating faster twist, etc.) All copper bullets are longer than traditional bullets of the same weight, as they are lighter per unit volume (lower density.)