I took into account the size of the IS fore arm and thought that maybe such a large caliber would fit. Then I realized maybe it wouldn't... so I added a buckler to give it an excuse to be a larger than normal gauntlet to house the 13mm twin shooters. However if it's still too big... then 11mm?
Though it is more like the sub machine gun really. A machine gun class is impractical to tote around
