my "it'll work for now" bag (going on 6 years):
I bring this pack and an ammo can. Last range trip I brought ~500 loose rounds for 5 of us (plus all the loaded mags).
What I bring:
Ears in small case (spare batts & soft ear plugs) x2; mine & wife's
3 10-mag sleeves; 1 for G17, 1 for G43X/48, 1 for misc pistols
Shoot n see targets
Maglula reloader
Pens
Eye pro
Misc small tools for RDS, screwdrivers, allen wrenches
Flashlight
Hoppes' hand wipes for shooters
Pistols for the day in a case or holster; usually 3 in the bag, one on my hip
I need to add binder clips to my bag for ill-equipped ranges and outdoor ranges.
My wife carries her own range bag (the Glock one) with 2-3 pistols.
Eye pro
Soft ear pro
Shoot n see targets
Spare ammo (boxed)
1 10-mag sleeve for G43/G48
Scarf in case of low-cut shirt that day
Spare t-shirt
To get: Another mag sleeve for the other handguns. The Glock bag is made for 2 guns, so maybe a bigger bag, but this is already near her weight limit for carrying. Maybe a roller suitcase with custom foam inside.
All mags are loaded before we get to the range. It makes for a heavy bag, north of 40#, but the bag takes it. I've thought about doing a different system altogether, like a Milwaukee PackOut or similar. But that means if it's all-in-one, that's a heavy b**ch to lift in and out of the truck, and it won't fit in the other cars. Most of our pistols are 9mm, but we have .380, .45, and 10mm, so I have to manage what rounds if we're bringing other calibers.
I need to work out my outdoor range package as well. Target stands, table, chair(s), targets, rifles, mags. All that other fun stuff.