The .30 Herret was designed in 1972 by Steve Herrett (Herrett’s Stocks) and gun writer Bob Milek while traveling from Twin Falls, Idaho, to Baker, Oregon. Rod Herett, Steve’s son, drove the car while the “designers” sat in the back seat and worked out the details of the above cartridge as well as the more potent .357 Herrett.

The .30 Herrett was designed specifically for single-shot pistols. It is based on the .30-30 Winchester case cut down to a length of 1.605 inches, and the shoulder was blown out to 30 degrees. Overall cartridge length is around 2.320 inches. It quickly illustrated improved accuracy and significantly lower extreme velocity spreads when compared to its parent cartridge when fired in a single-shot pistol. In addition to being more efficient than the .30-30 Winchester when fired from 10- and 14-inch barrels that are typical in Thompson/Center Contender pistols, the .30 Herrett produces less muzzle report. It quickly gained popularity among handgun hunters and silhouette (IHMSA) competitors. Although it became a popular barrel offering from Thompson/Center Arms, it was never adopted by SAAMI as a standard cartridge. As a result, no factory loads are available, making it strictly a handloading proposition.

Several powders gave good performance with various Sierra bullets, including Hodgdon H-110 and Winchester 296 (identical powders), Alliant 2400, Reloder 7 and IMR-4198. The best accuracy was obtained when cases were formed, fired, then reloaded the second time. Cases were sized just enough to allow the Contender action to close without resistance, which provided the best accuracy and extended case life. RCBS dies were used to form and load cartridges.