I don't believe so, as the case is fatter, and shorter, but I haven't found the data on this yet. They are talking about a shortage of the ammo untill acceptance of the New Rifles chambered to fire them. Watch for all the gun writers, saying how great they are. The thing about those writers, is they usually present the good side of a new Round/Rifle. If they didn't then the manufactures, will give their new product to a better writer. http://www.shortmags.org/shortmags/smclass.htm For the new WSSM (Winchester Super Short Magnum) cartridges, Winchester and Browning are both offering the 223 WSSM and 243 WSSM in new shorter action rifles (shorter by nearly 1/2").