Also a very good practice when selling, I sold a pistol package a few years ago, something about the buyers attitude was moody, so got my son to film it while I put all three mags through it.
Three weeks after selling said moody buyer says it's broken, & it arrived that way, demanding a full refund blah blah, what he didn't know was someone had given me a heads up that a week after I shipped it, he'd already tried to flog it on FB, for way more than he'd paid, while extolling it's excellent condition & fully working.
Needless to say he got a great big "f#ck off you chancer", & went very quiet.
Since then, on the very rare occasion that I sell rifs, I'll always make a vid of them working, cya lol.