Always a bit of contention.
It's pretty frowned upon, at least with experience, of gunfighters 'pumping' the pistols. The photo above would be an extreme case of pumping pistols, though some say you're sweeping yourself if your 'pumping', and you have one cocked gun behind the other, some say you can't sweep yourself, some say it's ok as long as the pistol behind is not cocked. I had a bad case of pumping for a spell, and was called out with a warning about 'unsafe gun handling', I got out of it as I was shown it is a sloppy way of doing things, leading to more misses and P's. But what do I know.
I recall reading something about this in the RO book, buried somewhere you wouldn't think of finding it.