The 224 Valkyrie catridge introduced by Federal Ammunition in 2017, is a 22 caliber rimless bottlenecked round developed for extreme long range applications, offering more energy and distance than 5.56 NATO. It is a necked down 6.8 SPC II case and remains supersonic past 1000 yards. Pro2a Tactical's 224 Valkyrie AR-15 Uppers are made with milspec or higher quality components and backed by our limited lifetime warranty.