Machine guns are designed to provide sustained automatic fi re, with the intent of riddling a single target with bullets, wounding or damaging multiple
targets within an area, or laying down suppression fi re.
Machine guns are primarily military weapons. They have little or no police or civilian use and are much rarer than rifl es, pistols, or shotguns. Because they spray out fi re indiscriminately, they are of little use to law enforcement, even to heavily armed SWAT teams. Law enforcement depends on carefully aimed shooting to minimize the risk of collateral damage to unintended targets, and machine guns are fundamentally incompatible with this role. Just the same, many large police departments have access to a few machine guns for emergency use.
Modern machine guns are dominated by designs so old that they might well be considered antiques. After World War II, many of the less successful designs were phased out of use, while those that had proven their worth in combat were retained. Today, many machine guns date from the World War II era or even earlier. The Browning M2 and the German MG3, for example, are both more than fi fty years old, and yet both are still in front-line service with the world’s best-equipped armies. Improvements in ammunition and mounts have been effective enough to allow these guns to remain valuable even on the modern high-tech battlefi eld. While more advanced designs have been developed, they have failed to entirely supplant the older weapons.
Most modern small arms are fed from box magazines with a few dozen rounds (usually, 20 to 30 at most). When the clip runs out, the shooter ejects it and loads a new one. This forces a pause in the fi ring of the weapon, which lets the action and the barrel cool down. Machine guns, on the other hand, are designed with sustained fi re in mind. Many are fed by belts that hold hundreds of rounds, making it possible to fi re a machine gun for an extended length of time—much longer than a clip- fed personal weapon. This necessitates the use of heavy barrels
and robust actions designed to absorb the heat and stresses of sustained fi re.
Even when using heavier barrels, machine guns often build up so much heat that their barrels begin to break down rapidly. In extreme cases, they can even begin to melt while being fi red. Many early machine guns featured water-fi lled jackets that encased the barrel to keep it cool, but this made them heavy
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and cumbersome weapons. Today, many machine guns are designed with quick-change barrels that can rapidly be detached and replaced in the fi eld with minimal tools.
Machine guns are generally large, heavy weapons, awkward to carry and fi re by hand. Because of their weight, machine guns are usually fi red from bipods or tripods, or from fi xed mounts on vehicles. Due to size and weight, all but the lightest machine guns are crewed by teams of two or three. One person is the gunner, who carries the weapon. The others serve as assistants to carry the tripod and spare barrels (if necessary) and to help feed the weapon. In addition, because machine guns can rapidly consume a huge quantity of am≠munition, the weight of the ammo soon becomes signifi cant as well. Assistant gunners serve an important role as ammunition carriers.
For civilian collectors, semiautomatic variants of some historically signifi cant machine guns are produced by specialty gunshops. To comply with gun control laws, the internal fi ring mechanisms in these weapons have been reworked to make them impossible to convert to automatic. These weapons are highly exotic, rare collectors’ items and are not often seen even among shooting enthusiasts.
Machine guns are broadly grouped into a number of categories.
Light machine guns (LMGs) are, as the name implies, relatively
lightweight and designed to be carried and fi red by one person. They fi re rifl e-caliber ammunition. Most are fi tted with bipods for station- ary use, but they can also be fi red from the hip, even while moving. LMGs are sometimes called squad automatic weapons, or SAWs.
General-purpose machine guns (GPMGs) emerged in the years
following World War II. The GPMG is a weapon that falls somewhere between the light machine gun and the medium machine gun in size and weight, and is capable of serving in either role. When used as an LMG, the GPMG is fi red from a bipod with a shoulder stock. When used as a medium machine gun, the GPMG is mounted on a tripod for long-range sustained fi re.
Medium machine guns (MMGs) are the next step up. They still
fi re rifl e-caliber bullets but are bigger and heavier than LMGs and are capable of signifi cantly higher rates of fi re. Though still readily portable, they are generally too heavy to be fi red except from a tripod. MMGs are also used with pintle or coaxial turret mounts on vehicles.
Heavy machine guns (HMGs) are too large to be easily carried,
and essentially require a large tripod or vehicle mount for stability. The most important reason for their large size is that they fi re large- caliber ammunition signifi cantly bigger than ordinary rifl e rounds. This gives them excellent long range and antiarmor performance. Because of their high power, HMGs are often used as antiaircraft weapons. HMGs are so heavy that several crew members are needed to move the weapon and its mount about. Furthermore, even when they are used on a tripod, their recoil is so strong that the legs of the tripod must often be weighed down with heavy sandbags to keep the weapon steady during fi ring.
Miniguns are the most complex machine guns. Like 19th-century
Gatling guns, these feature multiple barrels that rotate when the weapon is fi red. The rotating barrel design permits an astonishingly high rate of fi re, because the individual barrels have time to cool between shots. On most machine guns, the recoil force of fi red rounds drive the action. Miniguns, however, are mechanically com- plex enough that this doesn’t provide suffi cient power. As a result, an electric motor is added to drive the rotating barrel mechanism and feed in the ammunition—making an already complex weapon even more so.
Miniguns have been developed in a range of calibers and to serve a variety of roles, but their tremendous rate of fi re demands a huge quantity of ammunition—far more than can be easily car- ried by even a sizable crew. Consequently, miniguns are virtually always used on vehicle or aircraft mounts. They have proven es- pecially popular on helicopters, where the high rate of fi re helps
compensate for the diffi culty of hitting a target when fi ring from a moving aircraft. Although some miniguns can be used from tripod ground mounts, the sheer impossibility of moving a reasonable am- munition supply around without a vehicle to carry it means that miniguns are of limited military use in this manner.
d20 MODERN RULES
The rules in this section supplement those in the d20 Modern Roleplaying Game and apply to the fi rearms described in this chapter.
Profi ciency: One must have the Personal Firearms Profi ciency
feat to fi re a light machine gun, general purpose machine gun, or medium machine gun without taking a –4 penalty on the attack roll. One must have the Advanced Firearms Profi ciency feat to fi re on automatic without taking a –4 penalty on the attack roll.
One must have the Exotic Firearms Profi ciency (heavy machine guns) feat to fi re a heavy machine gun or minigun without taking a –4 penalty on the attack roll.
Belt-Fed Weapons: Weapons fed by a belt offer the advantage
of a large—or even continuous—source of ammunition. However, belt-fed weapons have some disadvantages.
Ammunition: Ammunition can be purchased in belts. A single belt consists of 100 bullets. Belts are available in ball or tracer am≠munition. The purchase DC for a belt of belted ammunition is equal to 6 + the purchase DC for a 20-round box of the ammunition type.
Loose ammunition can be hand-linked to create a belt. Doing so requires a supply of belt links (purchase DC 4 for a box of 100 links, which allows the creation of a 100-bullet belt). Belt links for one caliber of ammunition cannot be used to create a belt for a different caliber, but no restriction exists on the type of ammunition (for ex- ample, armor-piercing) that can be used. Creating a belt using loose ammunition and belt links takes 10 minutes per 100-bullet belt.
Belts can be combined or broken to any length. Two 100- bullet belts can be connected to create a 200-bullet belt. Likewise, a 100-bullet belt can be split to create (for example) one 40- bullet belt and one 60-bullet belt. Connecting or splitting a belt is a move action.
Loading: Loading a belt-fed weapon is a full-round action. A new belt can be connected to a loaded belt, provided that loaded belt still has 5 or more bullets. (If the loaded belt has fewer than 5 bullets left, a new belt cannot be connected and the weapon must instead be reloaded.) Connecting a new belt is a move action.
Assistance: A weapon with a belt of 50 or more bullets cannot be fi red by a single user unless it is on a bipod or mount. An assistant gunner is necessary to prevent the belt from twisting or tangling. Assisting is an attack action.
Belt and Box Feeds: Some machine guns accept both belts and box magazines. If a weapon is loaded with both a belt and a box magazine at the same time, it will not function. Only one ammuni- tion source can be used at a time.
Bipods: Unless noted otherwise, a machine gun comes equipped
with a bipod (see Bipods in the introduction for game rules).
Chambered Rounds: Any machine gun with a box magazine can
carry an extra cartridge in the chamber. To put a cartridge in the chamber, the weapon is loaded as normal. (Chambering a round is part of the normal loading process.) Then, the magazine is removed, an extra bullet is added (to replace the one that was chambered), and the magazine is reinserted. This process takes an extra full round beyond the time normally required to load the weapon.
Folding Stocks: A few machine guns feature folding stocks.
(Some weapons feature collapsible stocks; for game purposes, these are the same as folding stocks.) Folding a weapon’s stock grants a +2 circumstance bonus on Sleight of Hand checks made to conceal the weapon.
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Using a Large or larger weapon with the stock folded imposes a –1 penalty on all attack rolls. Folding or unfolding a folding stock is a move action. If you have a base attack bonus of +1 or higher, you can fold or unfold a folding stock as a free action when moving.
Hot Barrels: Machine guns fi re powerful rounds at a high rate of
fi re. In most roleplaying scenarios, barrel heat shouldn’t be an issue. However, if a mchine gun is fi red on automatic every round for 5 or more consecutive rounds, its barrel overheats and the weapon becomes unreliable.
Many machine guns are designed to allow a quick change of barrels. If an extra barrel is available (purchase DC equal to the weapon’s purchase DC – 10), it can be swapped in. Doing so takes two full-round actions, but if someone is available to help, the bar- rel can be swapped with a single attack action from each person.
An overheated barrel (one that has been fi red on automatic every round for 5 or more consecutive rounds) cools in 10 minutes, at which point it can be used again without the weapon being unreliable.
Optical Sights: Some machine guns feature optical sights.
Unless otherwise noted, optical sights function identically to standard sights.