Transformers G2 Jazz Backpack / Shoulder mount (might work for G1 Jazz & Stepper/Ricochet)

thingiverse

Simple backpack for G2 Jazz to shoulder mount the blue gun. Hole at the back and bottom may need to be drilled out to 3 mm and a thin smear of superglue or nail polish may be needed to make the 5 mm hole on top better fit the 5 mm handle of the gun. 3 mm holes may be used to hold the other gun or a missile using the encluded adapter (or you could run a length of hose between the two points). The spacing between the clips may need to be filed to fit, don't force it just file off material from the print until it fits. The missile clip is provided as a separate part and attached to the backpack print the bits which match the parts you have.