I have several old Colt pistols from around 1900. Three US Army 38 calibers, one US Navy 38 Caliber and two 22 WCF pistols. I have shot most of them at the range and find that a bit of blowback from one or two. Is this normal? Could these revolvers be blowing back some unfired grains of powder? If so, it would seem to me to be a bit dangerous since the grains of powder only need to catch fire to burn my face. Could this be a cartridge malfunction or the gun malfunction? I am using cartridges bought from reputable sources and not reloading my own. Any ideas here?