One-hand racking of shotguns? Grandpa Bruegger would have crapped his britches if he saw this type of shenanigans going on, and there sure would have been some butts bearing the imprint of his boondockers afterward... Now, Ma Bruegger always said "don't play ball in the house." Uh, I don't know what that has to do with this topic, but she sure said it a lot.
Er, ah, back to the topic: I think the one-hand rack is silly and is a maybe even a violation of the cardinal rules of gun safety ("never point a weapon at anything you don't intend to puncture and perforate").
What if you successfully load the weapon, but drop it? Sounds like a ND waiting to happen.
Please don't do this when I'm on the range. Leave the hollywood stuff to Arnold & Chow Yun Fat.