Around 1987, Randy Shelley, an employee of Dillon Precision, necked down 10mm Auto brass to 9 mm.

His goal was to get as much slow-burning powder in the case as possible in order to drive a 9 mm bullet to the velocity needed to qualify for the then-IPSC major power factor of 175.

A muzzle brake works by diverting gases perpendicularly relative to the barrel to reduce felt recoil.

[3] What put an end to the 9×25mm Dillon in competition was lowering of the USPSA major power factor from 175 to 165 (160 for IPSC competition) which improved the safety and effectiveness of .38 Super (and later 9x19 "Major") loads to a point that the extra rounds that would fit maximum-allowed length magazines outweighed any muzzle flip advantage from the 9×25mm Dillon.

According to the QuickLOAD database, the 9×25mm Dillon case can handle up to 250 MPa (36,259 psi) piezo pressure.

The Austrian 9×25mm Super Auto G pistol cartridge is probably the closest ballistic twin of the 9×25mm Dillon.

Dillon Precision makes the necessary resizing die, and reliable reloading data is easily found.