The 73-B4 has a short barrel made of steel. The folding stock is made of high-strength steel while half of the body is polymer and the other half is titanium. The gun relies on a pump-action method to which five 20 gauge shotgun shells are put down into a cylinder under the barrel, and each time the "pump" is pumped, it feeds one of these shells into the chamber while in the same process cocking the hammer.