Guess I'm a little puzzled by your question.
Many of us "combat" load "on the go" from either a side saddle or by carring extra shells in our jacket pocket. Shoot two, load two approach. Always topping off the magazine. If you ever run dry you simply chamber a shell using an over the top technique and then begin topping off your magazine while moving.
The other way, if range shooting, is to learn how to load twins or quads. Plenty of videos online demonstrating the technique but it takes lots of practice. Good technique for competition shooting but IMO of little use in the field or for home defense situations. Not sure how applicable this might be for shockwaves.
Don't know if this answers your question. Maybe you could clarify what you're asking.
Regards