RCBS products are usually fantastic, however in this instance I think they have done a small FUBAR. This is a die set for a straight wall cartridge which head spaces on the case mouth, but they include a seating die with a roll crimp feature. Here’s the stinking part, they offer a taper crimp die that you must buy separately. It makes them more money, but you end up with a die you won’t use. Other than that, they are great dies!