Re: the video...
I find his use of the handover technique pretty effective and agree (with him), that the slide release (particularly as he suggests, using the weak hand thumb) to be simpler and faster.
The term "slingshoting" has always, in my experience, been a term used by instructors to show how to pull back a slide as you operate a slingshot: you grab the loaded pouch/rear of the slide with thumb and fingers, pull it back , and then release it.
Until you used the term differently (as did the instructor in the video), I had never seen the term "slingshot" and "hand-over" used interchangeably. I've seen instructors address both methods in classes, and they considered them different techniques.
Hand-over, done properly lets you leave the gun up in front of the face, with the gun kept on or generally pointed toward the target. If you use the slingshot method as it was originally taught (and as the military taught it until after we sent troops to Afghanistan and Iraq) - you must pinch the rear of the slide and pull it back (just as you pull back the loaded pouch of a slingshot and then release it). Using THAT technique, you can't easily grasp the slide (in the "slingshot" manner) until you've moved the gun even more out of position.
- The old argument that slingshoting was a gross motor skill and using the slide stop/release was a fine motor skill has been pretty much debunked: they're arguably both fine motor skills -- as releasing a slide held in the "slingshot grasp" must also be done cleanly.
- The handover technique might truly be a gross-motor technique, but it does take longer, and that technique doesn't always work with the Beretta M9, because large hands can decock the weapon during the rearward stroke. The handover technique seems to work well with most other guns.
I've always used the off hand after inserting the mag, to move up to release the slide with several fingers to making a big "claw" that can't miss the slide stop/release, then moving back down to the support position. That said, I think I like the instructor's technique of using the offhand thumb as he reposition it to the grip, to release the slide.
I think I'll that technique a try for a while -- as it's a bit simpler than what I've been doing for years.