Daryl, Good question about that pistol. I read that the AutoMag used by Clint in Dirty Harry was a special, hand built pistol with an 8 1/2" barrel that could only fire blanks. The actual blank ammo may have been slightly necked to provide better feeding. Also I understood that the barrel had an internal restrictor to aid in function as it only fired blanks. Being a short recoil pistol. I wonder if (in addition to the barrel restricor) the bolt was actually locked or just held by spring pressure.