I participated in an action pistol shoot, today. On a couple of the stages, I needed to put one in the pipe to get enough shots. I notice that everyone else used a spare magazine to put one in the chamber, then switched mags. I only have two mags to begin with, so I locked the slide back, put one in the chamber, then dropped the slide. The rangemaster suggested that this was bad for my gun's extractor. I have a Glock 21SF. Can this do any harm?