I too, have a WWII Germantrainer in .22 cal. It is . KK-Wehrsportgewehr
Training rifle German from WWII, • Maker: Mauser-Werke A-G Oberndorf a./N
• Caliber: 22LR (Kal .22 Lang Fur Bochsen)
Mine was brought back after the war by my wife's uncle. He was an armorer in his outfit and later mounted a scope and cut back the stock to be a sporter. It misfires a lot so am thinking the firing pin is messed up or perhaps the spring on the firing pin is too weak.