Whether it's a cheaper option remains to be seen.
Search for an airsoft minigun to buy and your jaw will drop. Basic versions will set you back by around $3000, while a more authentic-looking machine can go for as much as $5000. Kuba_T1000 however promises an affordable alternative, with his DIY airsoft minigun.
Most of the gun is made of aluminum, to keep the total weight low. An “AmmoChute” system draws BBs from a wooden ammox box, and allows the minigun to attain a firing rate of over ten thousand rounds per minute. The C02 system provides the high-pressure air required to propel the BBs, and can be adjusted for different feet per second (or FPS, a common measurement airsoft enthusiasts use to gauge a gun’s power).
Kuba_T1000’s creation definitely pledges a complete (yet non-lethal) minigun experience, complete with a high-rate of sustained fire, and a massive supply of ammo. Unfortunately this DIY gun doesn’t rotate its barrel. According to Kuba, a 1:2 scale was required to keep costs down, and unfortunately this configuration leaves little space for a barrel rotation mechanism.
On top of that, Kuba is releasing construction plans piecemeal. His site is full of “coming soon” messages. But the FAQ makes it clear that specialized equipment is required to build the DIY minigun. It might be easier to spend for the store-bought counterpart after all.