Haley Strategic Partners Micro Rig, Sub Gun Insert, Insert, Black, SMG/PCC Magazines, Nylon MINS_SMG-2-1-BLK The SMG (SubMachine Gun) insert gives you a compact option for holding your submachine gun magazines in our Micro Chest Rig. This unique insert allows any size magazine to be inserted from a smaller MP5 (9mm) style magazine up to a larger Sig MPX style magazine. Hook and loop on both sides provide easy and secure installation.