I have these pouches for my first vest and they can hold anything though they are very big, taking up the entire lower left side of my vest. you can fit 2 full size ak mags in each pouch or a bottle of BBs or I also put my mp5 mags in there. Ive been too lazy to get another pouch(since My vest is all MOLLE) but these are suiting me fine as I only have 2 ak hicaps and 2 mp5 mags and I can put whatever else is needed in the other one, great buy, quality material, doesnt come off easy either.
These are my favorite magazine pouch. I use them for everything. Double AK mags, double M4 mags, Green gas, ammo, water bottles, etc. They are made strong and have plenty of adjustable velcro to contain whatever you want to carry.