http://www.ruger.com/news/2015-12-09.html
Sturm, Ruger & Company, Inc. (NYSE: RGR) is proud to introduce the new Ruger® GP100® chambered in .22 LR. This ten-round revolver offers an array of features designed for target shooting, small game hunting and recreational shooting.
Featuring a 5.50" half-lug barrel for improved handling and lighter weight, the Ruger GP100 in .22 LR is both durable and reliable. This new GP100 has an improved fire control system that uses a lighter mainspring than previous Ruger double-action .22 LR revolvers.