Winchester Super Short Magnum

Inventor John R. Jameson had developed and patented several designs for short magnum rifle cartridges.

[citation needed] Rather than pay royalties to Jamison Winchester and Browning halted production of all WSSM rifles.

The idea is that the short, fat powder column gives a more uniform load density and ignition rate and therefore a more consistent burn.

The .25 WSSM case which is almost a full inch shorter, can make use of an existing short action such as used by the 5.56 NATO and .223 Remington family of cartridges.

[citation needed] The relatively large diameter cases result in reduced magazine capacity and reliability along with a thinner bolt face, meaning it can break easily especially under the higher pressure of the cartridges.

[6] Additionally, Olympic arms created the .300 OSSM, which is a 25 WSSM necked up to .308” giving performance between 30-06 and .300 Winchester Magnum.