I have a 5.11 12 that I use for everything. 3 guns and ammo for each is pushing it but 2 is fine.
It's got 1 extra pouch on each side plus one on the rear. It doesn't look good anymore but it works well. 200 rounds of ammo in rear pouch. Muffs in one side pouch. Glasses, spare muffs and rags in the other pouch. Cleaning kit where the bladder would go and nearly the entire internal space is empty for the spare gun and mags. The other pockets keep screw drivers, pro grip, oil, springs and other crap organised well.
I'd like a similar backpack with built in side pockets like it has but can't find one.