.223 WSSM

The 223 Winchester Super Short Magnum (aka 223 WSSM) is not compatible with 223 Rem firearms. Don’t even try it. Introduced in collaboration between Browning and Winchester in 2003, the 223 WSSM is second only to the 220 Swift in terms of highest muzzle velocity for a .22 cal cartridge. A 55 grain 223 WSSM load delivers a muzzle velocity about ~600 fps faster than a standard 223 Rem, and is accordingly suitable for deer hunting (where state regulations allow, and assuming competent marksmanship).