Firestone U.S. M18 Recoilless Rifle .50 BMG Conversion Single Shot & Scope
SOLD FOR: $14,576.00
LSB#: LSB251005KD003
Make: Firestone
Model: U.S. M18 Recoilless Rifle (Converted)
Serial Number: 7238447 (additional component serials and ordnance numbers present)
Year of Manufacture: Original mid-20th century U.S. military production, later conversion
Caliber: .50 BMG
Action Type: Interrupted lug rotating breechblock, single-shot recoilless
Markings: The tube and receiver components are marked with U.S. military ordnance nomenclature including “M18,” “FIRESTONE,” “ORD. DEPT. U.S.A.,” and associated ordnance and drawing numbers. Additional serial and assembly numbers are present on the tube, receiver section, and internal components. All markings remain legible and are consistent with original U.S. military manufacture and later conversion work.
Barrel Length: The rifled portion of the .50 BMG conversion block measures approximately 36 inches. The total length, including the original 57mm portion of the recoilless rifle tube, measures approximately 59 inches overall.
Sights / Optics: The rifle retains original military-style iron sights. Also present is the original M18-pattern spotting rifle assembly mounted above the tube, complete with its optical and mounting components. All sighting elements appear intact.
Stock Configuration & Condition: The rifle is fitted with its original metal shoulder stock assembly. The stock shows honest handling and storage wear with a uniform gray finish consistent with the rest of the firearm. Padding and contact surfaces remain intact with expected surplus service wear.
Type of Finish: Parkerized and blued components
Finish Originality: Original military finish with later conversion components
Bore Condition: The .50 caliber rifled insert shows sharp rifling and a bright appearance with no obvious pitting noted during visual inspection. In this writer’s opinion, the bore rates 9.5/10.
Overall Condition: Approximately 80–85% of finish remains. The metal surfaces exhibit scattered handling marks, edge wear, and light surface oxidation consistent with military service life, long-term storage, and later civilian ownership. Markings remain clear and well defined. Overall condition rates Very Good.
Mechanics: The breechblock assembly operates smoothly by hand, and the action functions as intended for a single-shot conversion. The safety pin must be removed to fire. This firearm has been converted from its original recoilless configuration to fire .50 BMG ammunition in a civilian-legal format. We did not fire this firearm. As with all used firearms, a thorough cleaning may be necessary to meet your maintenance requirements.
Box, Paperwork & Accessories: Included with this rifle are original military accessories consisting of canvas pouches, straps/end covers, 2x Army M18 57mm Rifle Field Manuals, 3 slings, 2x recoilless rifle inert 57mm rounds with cases, extra shoulder pads, bore brush head, and the 2x spotting rifle assemblies. Accessories show age-appropriate wear and appear period correct to the M18 platform.
Our Assessment: The U.S. M18 recoilless rifle holds a distinctive place in American military history, having served as a lightweight anti-armor and infantry support weapon during the closing stages of World War II and into the Korean War. Manufactured by Firestone under U.S. Ordnance Department contracts, the M18 offered unprecedented portability for its class while delivering significant battlefield capability. The M18 recoilless rifle was developed near the end of the Second World War as a way to bring accurate, anti-tank artillery-style fire to infantry sections without having to use large anti-tank guns. The rifled barrel allowed for more accurate fire than the unguided rockets fired from something like a bazooka, while only sacrificing a moderate amount of penetrating power. Unlike normal, smaller rifles, the propellant gasses from a recoilless rifle round are projected out the back, pushing the warhead forward down the barrel. This results in nearly no recoil, hence the name. The M18 saw its most successful use in the Pacific Theater of the Second World War, where its lower penetrating power was not as much of an issue against Japanese armored vehicles. Though, it was primarily used for taking out emplacements. It had less effectiveness in the European Theater against heavily armored German vehicles. The M18 would continue to see service in the Korean War, though it would be superseded by larger and more effective recoilless rifles as well as the M20 Super Bazooka.
This example has been converted to a single-shot .50 BMG configuration, preserving the original tube, profile, and military character while adapting the platform for civilian ownership. The 36-inch rifled conversion unit housed within the original 57mm tube results in an imposing overall length of approximately 59 inches, underscoring the sheer scale and presence of this historic weapon system. The retention of original sights and the spotting rifle assembly further enhances its authenticity and display appeal.
With its authentic U.S. military markings, original accessories, and rare conversion history, this rifle stands as a centerpiece-level collectible for advanced U.S. ordnance enthusiasts. It represents a compelling blend of battlefield heritage, mechanical ingenuity, and visual impact seldom encountered on the open market. We are no longer offering layaway. Please see our high resolution photos and good luck on your bid! – L.S.
