This Push Thru die is designed to completely eliminate bulges near the case base, common in 40 S&W brass. By passing the case completely through the dies, the bulge is removed and the brass may be returned to service. The GRX die is currently only available for 40 S&W.
1911, Issue:11, Page:066
Big Book Catalog, Issue:67, Page:517
Sinclair, Issue:4B, Page:044