I saw a picture of and it pretty nasty. He lost the thumb back to the joint.Except for the unfortunate one who posted pictures of his thumb split open as he was seating a cap... I want to say it was on the sass wire but it may have been another site. Anyway, it’s often too early to say “never”.
His alias is Cuts Crooked and he posted it on the Cowboy Action City forum a couple of years ago as i recall.
Admittedly it was an anomaly but I use a capper and that brass loading rod thingy to seat caps.
Bunk