The China Lake Model (or China Lake Pump-Action Grenade Launcher) is a pump-action grenade launcher that was developed by the Special Projects Division of the China Lake Naval Weapons Center, which provided equipment to Navy SEALs.
M79 and XM148 grenade launcher, and the repeating T148E1 grenade launcher were unreliable, so they made a request to China Lake engineers. SEAL Teams were pleased with the resultant pump-action grenade launcher, since the tubular magazine held three 40x46mm grenades, and so with one grenade in the chamber, four grenades could rapidly be fired before reloading. In fact a skilled operator could fire four aimed shots before the first one landed. The grenade launcher was extremely light for its size, since a significant portion of it was made of aluminum. The weapon actually weighs 1½ pounds less empty than an empty M79. Loaded with 4 of the 8 ounce rounds, the 4 shot weapon weighs only 1/2 pound more than the single shot M79. Despite this advantage in firepower, it did have limitations as it could not reliably feed the more oddly-shaped 40mm grenades.
The pump-action grenade launcher featured leaf iron sights similar to the M79. The front sight is a fixed square notch. Depending on if the leaf is folded or not, the rear square notch is either fixed or adjustable from 75 to 375 m in 25 m increments.
Though meant for the SEAL Teams, a handful were used by Marine Force Recon and Army 5th Special Forces Group. Sources differ as to how many weapons were produced. One claims that between 20 and 30 were made. However, according to another source, only 16 were made. The highest original receiver number found is 50, but it may never have been made into a functional weapon. Since it was made on an ad hoc basis for special operations forces, it was not formally adopted and has no official designation. It is sometimes referred to as the "China Lake NATIC" or mistakenly as the EX-41. The EX-41 was a design concept created in the mid-1980s based upon the earlier China Lake Model Pump 40mm. The EX-41 was produced in prototype form a full 2 decades after the China Lake Model was produced. The China Lake NATIC designation is also erroneous as the weapon was never known by that designation.
An effort to produce an improved version of the weapon began in 1992 when Samuel "Dutch" Hillenburg a firearms writer specializing in military weapons teamed up with master machinist, Brian Fauci. In 2003, they achieved a breakthrough and were able to convince fellow writer and firearms enthusiast Captain Monty Mendenhall to finance their research effort. By 2004, they had a functional prototype and had formed Trident Enterprises Ltd. to continue their work on the project.
In June 2007, a taping of an episode of the popular military technology program, "Weaponology" was filmed which announced that Trident had been approached by Airtronic USA seeking to license their intellectual property in exchange for a royalty on each weapon produced.
Rather than proceed immediately with production of the original design based upon the Low Velocity 40x46mm round, Airtronic USA sought to make dramatic changes to the launcher to accommodate the 40x53mm High Velocity round used in the MK-19. While this change offered significant improvements in range (from 400m to 1500m) it presented immense challenges with dangerous chamber pressures and excessive amounts of recoil during firing. Additionally, the practical utility of a hand held grenade launcher was highly questionable. Due to the effects of wind drift and limited visibility, the 5 meter kill radius of a single 40mm round has limited effectiveness at 1500 meters.
Predictably, Airtronic USA experienced significant difficulties in their poorly conceived plan to make such radical changes to the original design and failed to ever produce a working high velocity variant.
In October 2009, Airtronic USA had cancelled its contract to manufacture any variation of the launchers.