I attended the SHOT show in January and queried both Ruger and a company I can't remember the name of (they make the aluminum receiver and barrel for the Ruger MKII's in different colors). The answer was basically the same. The .17 Mach2 achieves peak pressure quicker than the companies were expecting. They both advised that the straight blowback guns were experiencing bolts with very short lives. It seems that delayed blowback guns, like the Kimber produced pistol in 17 Mach2, do not have the same problems. It was implied that the future of straight blowback pistols in 17 Mach2 were doubtful.