The 7mm International Rimmed was developed as a silhouette cartridge for use in the Thompson Center single shot pistol. It is based on the 30-30 Winchester case necked down to 7mm (.284"), then fire formed to create a 38 degree shoulder angle. It was developed by Elgin Gates in the late 1970s as one of a series of wildcat silhouette cartridges ranging from 25 to 35 caliber for I.H.M.S.A. matches. The 7mm International Rimmed cartridge is similar to the commercial 7-30 Waters except for the sharper shoulder and less body taper. Both are made by necking down the 30-30 Winchester case. The 7mm International Rimmed is popular among handgun silhouette shooters and is a very effective cartridge for this sport.
This text is based on information from “Cartridges of the
World”, Hodgdon reloading manual, the cartridge designer and/or