9.6 Crew-Served Weapons, Sidearms, and Munitions
Key Takeaways
- The M249 light machine gun fires 5.56 mm from a 200-round drum, has a maximum effective range of 800 meters against a point target, and uses rates of fire of 85 rounds per minute sustained, 200 rapid, and 850 cyclic.
- The M240B medium machine gun fires 7.62 mm, has a maximum effective range of 1,800 meters on a tripod, and uses rates of fire of 100 rounds per minute sustained, 200 rapid, and 650 to 950 cyclic.
- The M2 .50 caliber heavy machine gun has a maximum effective range of 1,830 meters against a point target and requires headspace and timing to be set before firing.
- The M17 and M18 Modular Handgun System replaced the M9 as the Army sidearm, is chambered in 9 mm, and has a maximum effective range of about 50 meters.
- The M67 fragmentation grenade weighs 14 ounces, has a 4 to 5 second fuze delay, a casualty-producing radius of 15 meters, and an average throwing distance of about 35 meters.
Crew-Served Weapons, Sidearms, and Munitions
Board Primer: Weapons questions rarely stop at the M4. A team leader is expected to know the systems in the squad and platoon, their ranges and rates of fire, and how to make each one safe. Memorize the numbers, but be able to say what they mean — a maximum effective range is the distance at which a trained Soldier can expect a 50 percent probability of hit on a given target, not the distance the round can travel.
1. The Four Weapons Safety Rules
Every weapons answer opens with safety:
- Treat every weapon as if it is loaded.
- Never point the weapon at anything you do not intend to destroy.
- Keep the weapon on safe and your finger off the trigger until you intend to fire.
- Know your target and what is beyond it.
The clearing sequence for any weapon: place the weapon on safe, remove the source of feed (magazine, belt, or drum), lock the bolt or slide to the rear, and physically and visually inspect the chamber and receiver before releasing the bolt and closing the weapon.
2. Squad Automatic Weapon — M249
| Characteristic | Value |
|---|---|
| Caliber | 5.56 mm |
| Operation | Gas-operated, air-cooled, belt-fed (also accepts a magazine in an emergency) |
| Standard load | 200-round drum or belt |
| Maximum effective range | 800 m (point target), 1,000 m (area target) |
| Maximum range | ~3,600 m |
| Rates of fire | Sustained 85 rpm; rapid 200 rpm; cyclic 850 rpm |
| Barrel change | Sustained: every 10 minutes. Rapid: every 2 minutes. |
3. Medium Machine Gun — M240B
| Characteristic | Value |
|---|---|
| Caliber | 7.62 mm |
| Operation | Gas-operated, air-cooled, belt-fed |
| Maximum effective range | 1,800 m (tripod-mounted), 1,100 m (bipod, area target) |
| Maximum range | ~3,725 m |
| Rates of fire | Sustained 100 rpm; rapid 200 rpm; cyclic 650–950 rpm |
| Barrel change | Sustained: every 10 minutes. Rapid: every 2 minutes. |
4. Heavy Machine Gun — M2 (.50 cal)
| Characteristic | Value |
|---|---|
| Caliber | .50 caliber (12.7 mm) |
| Operation | Recoil-operated, air-cooled, belt-fed |
| Maximum effective range | 1,830 m (point target) |
| Maximum range | ~6,800 m |
| Rates of fire | Sustained less than 40 rpm; rapid more than 40 rpm; cyclic 450–550 rpm |
| Critical setting | Headspace and timing must be set before firing. Improper headspace or timing is the single most dangerous error on this weapon. |
5. Grenade Machine Gun — MK19, Mod 3
| Characteristic | Value |
|---|---|
| Ammunition | 40 mm grenade, belt-fed |
| Maximum effective range | 1,500 m (point target), 2,212 m (area target) |
| Rates of fire | Sustained 40 rpm; rapid 60 rpm; cyclic 325–375 rpm |
| Employment | Suppression of area targets, light armor, and dismounted infantry |
6. Sidearm — M17 and M18 Modular Handgun System
The M17 (full size) and M18 (compact) replaced the M9 Beretta as the Army's standard sidearm.
| Characteristic | Value |
|---|---|
| Caliber | 9 mm |
| Operation | Semi-automatic, short recoil, striker-fired |
| Magazine capacity | 17 rounds standard (21-round extended magazine available) |
| Maximum effective range | ~50 m |
| Safety features | Manual thumb safety plus internal drop safety |
Clearing an M17/M18: place on safe, remove the magazine, lock the slide to the rear, and inspect the chamber.
7. Grenade Launcher — M320
The M320 replaced the M203 and mounts under the M4 or is fired standalone with its own buttstock.
| Characteristic | Value |
|---|---|
| Ammunition | 40 mm low-velocity grenade |
| Maximum effective range | 150 m (point target), 350 m (area target) |
| Feature | Side-loading breech, which allows longer projectiles than the M203 |
8. Hand Grenades
| Grenade | Purpose | Key data |
|---|---|---|
| M67 fragmentation | Kill or wound | 14 oz; 4–5 second fuze; 15 m casualty radius; ~35 m average throw |
| M18 colored smoke | Signal and mark | Burns 50–90 seconds; red, green, yellow, violet |
| AN-M8 HC white smoke | Screen | Burns 105–150 seconds |
| M84 stun (flash-bang) | Distract and disorient | Non-lethal; used in close-quarters entry |
| ABC-M7A2/A3 CS | Riot control | Irritant |
Grenade employment: the standard commands are "FRAG OUT" for a fragmentation grenade and the corresponding call for other types, given loudly so the team can react.
9. Classes of Machine Gun Fire
Board members frequently follow a range question with a doctrine question:
| Classification basis | Categories |
|---|---|
| With respect to the ground | Grazing fire (no more than 1 meter above the ground) and plunging fire |
| With respect to the target | Frontal, flanking, oblique, and enfilade fire |
| With respect to the gun | Fixed, traversing, searching, traversing and searching, swinging traverse, and free gun |
Enfilade fire — where the long axis of the beaten zone coincides with the long axis of the target — is the most desirable class of fire because it produces the maximum effect for the ammunition expended.
Final protective line (FPL): a predetermined line along which grazing fire is placed to stop an enemy assault. Where terrain prevents an FPL, a principal direction of fire (PDF) is assigned instead.
10. Accountability
- Sensitive items — weapons, night vision devices, and communications security equipment — are accounted for by serial number, by physical count, and by sight, at least at the start and end of every duty period and any time the situation changes.
- A missing sensitive item is reported immediately through the chain of command; there is no acceptable delay.
- DA Form 2062 (Hand Receipt/Annex Number) documents sub-hand-receipted equipment down to the user.
What is the maximum effective range of the M240B machine gun when it is tripod-mounted?
What are the rates of fire for the M249 light machine gun?
What must be set on the M2 .50 caliber machine gun before firing?
What are the fuze delay and casualty-producing radius of the M67 fragmentation grenade?