H&K has made a very interesting step with their MP5 .22 LR variations. The pistol variant is a lot of fun to shoot and runs nicely for a rimfire blaster. The MP5 .22 LR pistol is a direct-blowback, semi-auto handgun. The barrel is 8.5 inches in length. Although there are no slots for mounting optics, the rimfire versions are compatible with claw mounts since they are precise reproductions of the original MP5. The .22 LR MP5 handgun is intended to be used with high-caliber and high-velocity standard ammunition.