Magazine Inserts
Magazine insert can fit in any Crown Arms chest rig with the hook and loop orientation of velcro. They can be made to any size, so select how many cells you want and specify what size each cell should be, such has "two rifle and two pistol cells, with the pistols of the left". Which would make an insert with two glock pistol magazine cells on the left side of your body and two 5.56 rifle magazines on the right.
All material is MADE IN THE USA from Rockywoods Fabrics
https://www.rockywoods.com/