I have in my possession a London Bridge Trading chest rig/rack. Four pouches each good for two twenty-round 7.62x51 magazines. -or- three 30 round 5.56 STANAG magazines. Works great for this purpose of storing and transporting your battle load. It certainly worked well for me during an OEF deployment to Afghanistan.
Sometimes however, you need to transport something other than ammo and you don't need anything to large on you back. This was the case tonight, 04July2019...
I managed to pack 3/4 of a four pack of GTBs*.
Put this on backwards after filling the pockets and presto, a beer carrier!