In 2004, a trio of small arms enthusiasts began an effort to reproduce the Vietnam-era China Lake 40mm pump action grenade launcher. They displayed their first prototype at SHOT Show, and (not surprisingly) got quite a lot of interest in it. Their production plans quickly went form 1 to 3 to 10 and then to 50 units…far too many to built one by one by hand as the prototype had been. Looking for a source for barrels, they wound up in contact with the Airtronic corporation. Airtronic was then primary contractors making M203 grenade launchers for the US military. They could easily produce a few dozen barrels, but they expressed an interest in mass producing the gun.
At about the same time (in the aftermath of the Battle of Fallujah), the USMC began a process to find a multiple-shot 40mm launcher. Specific interest was expressed by the Marines in the China Lake, and Airtronic began to change the original design to better fit modern military needs. Some of these changes were simple and suitable, like replacing the old M79 iron sights with Picatinny rail for modern optics, and replacing the stock with an AR-pattern pistol grip and buttstock. The really problematic change was an attempt to lengthen the receiver and allow the gun to use the high pressure grenades of the Mk19 automatic grenade launcher. This would not have proven feasible, but the project never got as far as a completed, firing prototype.
Instead, questions of ownership, licensing, and money broke out. The original three partners and Airtronic wound up in a lengthy and destructive lawsuit, which would lead to Airtronic declaring bankruptcy and no complete guns, either original pattens or modernized, being completed. This prototype is the only surviving example. The USMC would end up trialling the South African Milkor MGL-140, modifying it a bit, and ultimately adopting it as the M32A1.
Many thanks to Dutch Hillenburg for making this video possible!