Complex sentence: Currently there are only a few die makers who manufacture and market bullet swaging equipment, three die and equipment makers CH/4D, RCE, and Corbin manufacture the bulk of bullet swaging equipment in the United States.
Split into simpler sentences: Currently there are only a few die makers who manufacture and market bullet swaging equipment. Three die and equipment makers, CH/4D, RCE, and Corbin, manufacture the bulk of bullet swaging equipment in the United States.