LMT Quadrant Rail Mount Sight for M203 Grenade Launcher

Original price was: $25000.Current price is: $19900.

Category: Product ID: 825


LMT Quadrant Rail Mount Sight for M203 Grenade Launcher

LMT Quadrant Rail Mount for sale

Description: LMT Quadrant Rail Mount

Rail Mounted Quadrant Sight for the M203, 50-400 meters.
100% Made in the USA


The Lewis Machine & Tool (LMT) 9-inch M203 2003 rail-mounted grenade launcher is a great example of a versatile weapon system. A friend of mine succumbed to the urge and went through the NFA process to acquire one. The LMT 40mm M203 is covered under the NFA Destructive Device auspices. Many do not realize that a 40mm launcher is possible for a mere “civilian.” While the 40mm launcher is most associated with high-explosive (HE) rounds commonly used in the military, these are not the most practical for the civilian. If HE rounds are located, a hard task in itself, civilians are required to obtain a $200 tax stamp for each HE round, then pay the asking price for the round and then comply with storage regulations.

Do not despair, however, as there are a surprising number of options available in terms of 40mm rounds and adapters on the market for the LMT M203 2003 launcher. For example, adapters to fire shotgun shells, multiple .22 LR rounds in one trigger pull and flares exist. Today’s 40mm ammunition is diverse, with training, illumination, IR illumination, CS gas, flare, smoke, buckshot and less-lethal loads available.

Versatile 40mm

The 40mm’s flexibility and lethality are the main reasons why it has been around since 1961 in the form of the M79, which was later replaced by the M203 in 1969. The M79 was a standalone weapon resembling a break-open, single-shot shotgun. The M203 was designed as an under-barrel device attached to a rifle. Since a grenade is not always the best choice for a given engagement, not to mention the weight associated with each 40mm round making carrying enough problematic when in the field by an individual, an under-barrel system has the advantage of allowing its user to also carry a rifle and easily switch between the two, thus staying relevant to the unit, no matter the situation. The original M203 is intended for permanent attachment to the rifle.

The LMT M203 2003 rail-mounted grenade launcher’s close lineage to the M203 is evident aesthetically. The updated LMT M203 40mm variant is more adaptable to use with a variety of rifles due to its improved mounting method. A standalone pistol grip rail is also an option. LMT offers both 9- and 12-inch tube lengths. The LMT launcher is designed for use with the LMT Monolithic Rail platforms and other Mil-Std-1913/STANAG rail systems. The LMT M203 variant is much easier to install and remove in the field than the original M203. It features a 1-in-48-inch twist rate. Here lies a major difference between the 40mm launcher and the 37mm variants that exist in the civilian world. The 40mm is rifled, whereas the 37mm launchers are smoothbores and do not fall under NFA regulations due to being considered more of a pyrotechnic device. The LMT M203 weighs approximately 3 pounds and measures 12.5 inches long.

“The 40mm weapon system was developed as a cross between a rifle grenade and a mortar with intent to increase a platoon’s firepower.”

A brief word on 40mm ammunition is in order. The LMT M203, as with most handheld grenade launchers, uses low-velocity 40x46mm rounds. A higher-velocity 40x53mm round is typical in mounted and crew-served weapons. The two 40mm cartridges are not interchangeable. The rounds feature a High-Low Propulsion System to help manage recoil forces. The cartridge casing contains a cup-shaped “high-pressure chamber” in the bottom. On firing, the propellant builds up pressure until it breaks through the copper cover, venting out to the “low-pressure chamber” and sending the 40mm down the tube at approximately 250 fps. The listed effective range of the M203 is 160 yards, with 450 yards being the maximum.

The 40mm weapon system was developed as a cross between a rifle grenade and a mortar with intent to increase a platoon’s firepower. The M203 launcher is intended to be used as close fire support against point and area targets. Its primary purpose is to engage enemies in spaces that cannot be reached by direct fire. There are at least eight different rounds I discovered mention of for the M203 in the military arsenal: M406 HE rounds; M433 HE dual-purpose rounds; M585 white star clusters; M651 tactical CS grenades; M781 practice rounds; star parachutes (white, green and red); ground markers (red, green and yellow); and M576 buckshot (“beehive”). Other rounds exist for the 40mm, both in the less-lethal and military realms.

The LMT M203 2003 launcher can be labeled as a third-generation 40mm launcher. For reference, the M79 is first generation, the M203 is second generation, and third-generation models are standalone launchers that are multifunctional—they can be either attached to a base rifle platform or function on their own. Third-generation systems frequently feature the increased use of aluminum, composites and polymers within the manufacturing process, and generally rely upon a side-opening breech, rather than the M203’s slide-forward breech mechanism. By opening to the side, the third-generation systems are better capable of accepting 40mm rounds that are longer in length than the original M583 parachute flare round, which is 5.25 inches long. This is a significant and important feature as increasing numbers of less-lethal and medium-velocity 40mm rounds enter the market.


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