Jolly,
My shortkit, purchased from BPI I believe, is simply a 1/4" steel plate that fits under the spring and shell holding plate. The offical nae appears to be "Quick hull length converter". I do know it works on my 600 20 ga. and Sizemaster 12 ga. Simply relieve the spring pressure and slip the plate under the shell holder plate. No need buy new dies. Happen to have a BPI brochure under my elbow....part number you're looking for is MEC 1308849. $25.99 from BPI. Likely cheaper from Amazon or Ebay if you're so inclined.
