The 240B machine gun stands as a benchmark in reliability and performance, making it a top choice for military enthusiasts, collectors, and tactical professionals. Our comprehensive shopping guide covers everything you need to know—from must-have accessories to maintenance tips—ensuring you get the most out of this powerhouse. Discover why the 240B remains a trusted and appealing option for discerning buyers.

Variations and Applications of the M240B Machine Gun

Variant / Application	Primary User	Mounting Options	Weight	Special Features	Typical Role
M240B (Standard)	Army, Marines, USCG	Bipod, Tripod, Vehicle	~27.6 lbs	Hyd. buffer, Picatinny rail, quick-change barrel	Infantry, vehicle, and static defense
M240 (Coaxial)	Army	Armored vehicles	~25.6 lbs	Designed for tank use, remote firing	Coaxial tank/vehicle general purpose gun
M240L (Lightweight)	Army, Marines	Bipod, Tripod, Vehicle	~22.3 lbs	Titanium for reduced weight	For infantry requiring lower carry weight
M240H	US Air Force	Aircraft, Vehicle	~25 lbs	Modified for aircraft, double spade grip	Aircraft door gunner, vehicular defense
M240G	Marines	Vehicle, Tripod, Bipod	~25.6 lbs	Vehicle-mount optimized, minor variant from B	Mounted on Marine vehicles/ground roles
Barrett 240LW/LWS	Military, Law Enf.	Bipod, Tripod	~20 lbs	Advanced lightweight design, materials	Mobility-focused operations

Key Features of the M240B Machine Gun

Robust Design for Reliability

The M240B is engineered for durability and operational reliability under extremely demanding conditions. It is renowned for firing tens of thousands of rounds with minimal malfunction. This reputation stems from its:
– CNC-machined steel receiver for solid construction
– Cold hammer-forged barrel with a hard-chromed bore to extend life and accuracy
– Open-bolt operation to prevent cook-offs and keep the system cool

Fully Automatic, Belt-Fed Operation

The M240B is a fully automatic, belt-fed, gas-operated machine gun. This design enables:
– Sustained rapid fire (650-950 rounds per minute, typically around 700 RPM in field use)
– Compatibility with standard NATO 7.62x51mm ammunition
– Quick reloading from 100-round linked belts, supporting continuous suppressive fire

Advanced Mounting Options

Flexibility in deployment is a highlight. The M240B can be:
– Fired from its integrated bipod for mobile fire support by a single gunner
– Mounted on the lightweight M192 tripod for maximum accuracy and stability in defensive roles
– Attached to vehicles, helicopters, and boats for mobile and static applications

Quick-Change Barrel System

To avoid barrel overheating during extended fire, the M240B’s quick-change system allows:
– Easy and safe swap of hot barrels for cool spares
– Barrels are specific to each gun and must not be swapped between units for safety

Ergonomic Controls and Modern Features

Operators benefit from:
– Large, glove-friendly controls for use in all environments
– Cross-bolt safety (safe/fire)
– Top-mounted Picatinny rail for optics and night vision devices
– Simple, robust iron sights adjustable for both windage and elevation up to 1,800 meters

Crew-Served Operation

While the M240B can be used solo, doctrinally, it is part of a three-person team:
– Gunner (operates and fires the weapon)
– Assistant gunner (helps reload, change barrels)
– Ammo bearer (supplies ammunition and assists as needed)

---

Usage and Safety Considerations for Home or Hobbyist Use

Legal Considerations

• The M240B is a military-grade, fully automatic weapon. Civilian ownership in the United States is heavily restricted and regulated under the National Firearms Act.
• Some semi-automatic-only variants or inert (deactivated) display guns may be available, but require additional permits and background checks.

Safe Handling Practices

Due to its size, weight, and power, it’s important to:
– Always treat the weapon as loaded, following basic firearm safety rules.
– Ensure correct loading and unloading procedures to avoid accidental discharges.
– Use proper PPE (hearing and eye protection); the 7.62mm cartridge produces significant noise and blast.
– Only the trained, designated gunner should handle firing, with support from crew members as recommended.

Storage and Maintenance

• Store in a secured, locked area, ideally in a reinforced gun safe. Due to its weight, ensure the area is suitable for large, heavy firearms.
• Regular cleaning is essential, especially after firing in adverse environments. The M240B is highly resistant to fouling but performs best with proper lubrication and care.
• Routine inspection of the barrel, feed mechanism, and gas system for wear or debris is strongly recommended.

Range and Hobby Uses

• Suitable for specialized shooting ranges equipped to handle full-auto 7.62mm machine guns. Ensure the range meets safety and backstop requirements.
• Collectors may seek inert models for display due to historical significance, especially those with original markings and accessories.

---

Practical Tips and Best Practices for Choosing and Using an M240B

1. Assess Your Purpose

2. If buying for a collection, focus on provenance, accessory completeness, and condition. For practical use (e.g., demonstration, museum firing), ensure you can legally acquire and use it, or consider semi-auto variants.

3. Understand the Variants

4. Standard M240Bs are heavy but robust; lighter variants (M240L or Barrett 240LW) offer portability but may be harder to find or more costly.

5. Consider which mounting systems (bipod, tripod, vehicle mount) you need for your intended use.

6. Evaluate Accessory Needs

7. Essential accessories include: extra barrels, cleaning kits, spare links, tripods, and ammo boxes.

8. For display, original military-issued slings, manuals, and period-correct optics increase value.

9. Training and Teamwork

10. Machine guns like the M240B are best operated by a team—train with your group for smooth barrel changes, reloading, and malfunction clearing.

11. Practice engages controlled bursts to manage recoil, conserve ammunition, and maximize accuracy.

12. Ammunition Considerations

13. Use only high-quality, NATO-standard 7.62x51mm linked ammunition.

14. Store ammo in a cool, dry place and inspect belts for corrosion or damage before use.

15. Maintenance Schedule

16. Clean after each use, focusing on the barrel, gas system, and feed tray. Lubricate all moving parts.
17. Inspect often for loose or damaged parts, replacing when needed to maintain reliability.

---

Comparison Table: Technical Features of M240B Variants

Feature / Model	M240B	M240L (Light)	M240G	Barrett 240LW
Operation	Gas, open-bolt	Gas, open-bolt	Gas, open-bolt	Gas, open-bolt
Caliber	7.62x51mm NATO	7.62x51mm NATO	7.62x51mm NATO	7.62x51mm NATO
Weight	~27.6 lbs	~22.3 lbs	~25.6 lbs	~20 lbs
Barrel Length	24.7 in	24.7 in	24.7 in	18–20 in (est.)
Overall Length	49.7 in	49.7 in	49.7 in	42–46 in (est.)
Rate of Fire	650-950 rpm	650-950 rpm	650-950 rpm	600–900 rpm
Effective Range	Up to 1,800 m	Up to 1,800 m	Up to 1,800 m	~1,200–1,500 m
Mounting Options	Bipod, Tripod, Veh.	Bipod, Tripod, Veh.	Bipod, Tripod, Veh.	Bipod, Tripod
Key Features	Std. variant	Titanium/lightweight	Marines vehicle-use	Lightest in class
Crew-served	Yes	Yes	Yes	Yes
Civilian Variant	Rare, restricted	Rare, restricted	Rare, restricted	Semi-auto only

---

Related Video

Conclusion

The M240B machine gun stands as a pinnacle of reliability, versatility, and firepower. Its robust construction and ease of operation make it a favorite among military users, while its historical significance attracts collectors and enthusiasts. Choosing the right variant depends on your intended use—whether for collection, display, or (where legally possible) live fire. Owning or handling such a powerful machine gun brings both immense satisfaction and serious responsibility. Safety, legal compliance, and regular maintenance are paramount for anyone privileged enough to own or operate an M240B.

---

FAQ

1. What is the M240B machine gun?
   The M240B is a belt-fed, air-cooled, gas-operated general-purpose machine gun chambered in 7.62x51mm NATO, widely used by the U.S. military for infantry support, vehicle mounting, and static defense. It is praised for its reliability and sustained rate of fire.

2. Can civilians legally own an M240B?
   In most countries, including the U.S., civilian ownership of fully automatic M240Bs is heavily restricted. Only pre-1986 transferable machine guns are legal for civilians, and few (if any) exist. Some semi-automatic variants or inert display guns may be available with proper licenses.

3. What are the main differences between the M240B and M240L?
   The M240L is a lighter variant of the M240B, using titanium components to reduce weight by about 18%. This makes it easier for infantry to carry but is more expensive and produced in smaller quantities.

4. How much does an M240B weigh?
   The standard M240B weighs approximately 27.6 pounds without accessories or ammunition. Lighter variants, like the M240L or Barrett 240LW, can weigh as little as 20-22 pounds.

5. What kind of ammunition does the M240B use?
   It fires 7.62x51mm NATO cartridges. Standard types include ball, armor-piercing, tracer, blank, and dummy rounds. Belts are often linked in 100-round bandoleers for quick loading.

6. What is the M240B’s effective range?
   The M240B, when mounted and properly sighted, has an effective range of up to 1,800 meters with the tripod for area targets and roughly 600–800 meters for point targets with the bipod.

7. Is the M240B difficult to maintain or clean?
   While robust and tolerant of harsh conditions, regular cleaning and lubrication are essential. The design allows for relatively straightforward field stripping, but post-usage cleaning, especially after training in dirty environments, is important to maintain functionality.

8. How many people are required to operate the M240B effectively?
   Doctrine prescribes a three-person crew: a gunner, an assistant gunner (also called A-gunner), and an ammo bearer. This ensures maximum effectiveness, efficient loading, quick barrel changes, and continuous supply of ammunition.

9. Can the M240B be used for home defense?
   Due to its size, firepower, and legal restrictions, the M240B is not suited for home defense. Its intended roles are military or law enforcement support and static defense. Civilian users typically own inert or semi-automatic display versions for collection and historical purposes.

10. What accessories are available for the M240B?
    Common accessories include: spare barrels, tripods, cleaning kits, slings, optics (day or night), laser aiming modules, ammunition boxes, and vehicle mounting brackets. Original accessories enhance collector’s value and functionality.

---