The M41 “Pulse Rifle” with attached U1 underbarrel grenade launcher

The M41 submachine gun was a trend-setting weapon designed by retired United States Marine Corps Colonel Jonathon LaForce in 2027. Unlike most firearms of the time, it utilized not only caseless ammunition, but an electronic ignition system instead of being hammer- or striker-fired.

It was adopted by the USMC in 2028, and is issued to units fighting in certain urban environments or on space stations or ships, as features like its caseless, explosive-tipped ammunition make it particularly useful for those types of combat. However, some of those same advantages also limit its use, as the caseless ammunition is rather sensitive to outside contaminants. Although the weapon is technically a submachine gun, as the first pulse-fired weapon adopted by the US military, it is often known simply as the “pulse rifle”.

Weapon Designation:Submachine Gun, 10mm, Caseless, Pulse-Fired, M41
Type:Submachine Gun
Place of OriginUnited States:
In Service:2027-present
Production History:
Manufacturer:Armat Battlefield Systems
Weight:6.38 lb (2.9 kg) (empty, without U1 grenade launcher)
Length:33 in (840 mm) (stock open)
27.36 in (695 mm) (stock closed)
Barrel Length:9.72 in (247 mm)
Cartridge:10x24mm Caseless
Action:Roller-delayed blowback, electronically ignited cartridges
Rate of Fire:900 rounds/min cyclic
Muzzle Velocity:1,663 ft/s (507 m/s)
Muzzle Energy:1,290 ft/lbs (1,749 Joules)
Effective Range:200 m (219 yd)
Feed System:30-round detachable box magazine
Sights:Iron sights, M86A1 CQO red dot sight


Jonathan LaForce was a retired USMC Colonel who began work on the M41 in 2026, incorporating his combat experiences during his service. In late 2026, the USMC became aware of his design, and was so interested that they not only encouraged him to continue developing it, but even borrowed concepts from the weapon for a full-sized service rifle utilizing caseless, electronically-fired ammunition, which was developed by Armat Battlefield Systems alongside LaForce’s private endeavor. However, the XM37 proved to have only mediocre reliability and the fragility and susceptibility to contamination of the caseless ammunition led to the rifle being considered unacceptable for the harsh environments in which it would be used, and the USMC refused to accept it. However, they retained interest in the XM41, because of a perceived ability to deploy it in more controlled environments where ammunition contamination was less likely, and also because of the potential of the explosive-tipped rounds it fired, which were also designed by LaForce.

In late 2027, LaForce completed his design and it was trialed and accepted by the USMC as the M41 submachine gun. Although their XM37 had been rejected, Armat Battlefield Systems quickly purchased a production license for the M41, resulting in LaForce receiving sizeable royalty payments for the rest of his life. Armat began full production of the M41 in early 2028.

Despite some limitations, the M41 quickly built a reputation for being a reliable, effective weapon, and with the passage of the Weapons Development Ban, part of the Cooperative Exploration Treaty, in 2036, weapons technology development became drastically limited, to the point that it was virtually impossible to design a more technologically-advanced firearm and so the M41 continued to see service as the USMC’s only submachine gun model until the Marine Corps’ dissolution in 2101, after which it was immediately adopted by the newly-formed United States Colonial Marines.


The M41 was the first firearm designed to use titanium aluminide alloys in its construction. This gives it exceptional strength and light weight. It is a compact weapon, measuring only 33 inches with the collapsible stock in the extended position and 27.36 inches with the stock collapsed. This makes it comparable to the M933P carbine in terms of length, although it weighs almost two pounds more and the roles filled by the two weapons are rather different. It has a distinctive forward handguard with eight vent slots cut in each side, and a long cut-out along the top.

In addition to its electronic firing mechanism, the M41 features an ammunition counter display on the right side of the magazine well. It can be dimmed for operations in dark areas, or shut off completely. Both it and the firing mechanism are powered by a battery installed in the gun’s pistol grip. The M41 also has a pair of laser aiming modules installed in its prominent carry handle, just ahead of the emergency ejection port. The left laser is an infrared system and the laser dot can only be seen with night vision goggles or the M10 helmet’s infrared sight, while the laser on the right emits a green dot that can be seen with the naked eye.

The M41 features a charging handle on the right side, used for chambering a round when a new magazine is inserted with the chamber empty, and also for ejecting failed or training-use rounds. Although LaForce’s decision to only put the charging handle on one side was somewhat controversial because it was not considered ambidextrous, LaForce himself demonstrated during USMC trials that a right-handed user could easily slip their left hand under the carry handle and over the receiver to reach the handle, while a left-handed user could reach the handle directly with their right hand.


The M41 fires caseless ammunition, which comes with several unique advantages and disadvantages. Although the removal of the extraction and ejection phases of the firing cycle improve reliability and the caseless ammunition weighs less per round than an equivalent cased cartridge, the caseless rounds are both fragile and susceptible to contamination by any liquid they might come in contact with, including water, left-over cleaning solvent, and potentially even excessive lubrication. In a firearm firing cased ammunition, each spent casing acts as a heat sink, carrying a significant amount of heat away from the weapon, while in a firearm that uses caseless ammunition, that heat remains in the weapon and continues to build up, leading to overheating and even ammunition cook-off. Because of this, the M41 is somewhat unsuited for periods of sustained fire.

Despite its weaknesses, the M10-210 round is also highly effective. Fired from the M41’s 9.72 inch barrel, with a rifling twist rate of 1:16, the 210-grain round reaches a muzzle velocity of 1,663 feet per second, and a muzzle energy of 1,290 ft/lbs. This is further augmented by the use of an explosive tip in the bullet. The explosive material used, MSHX, or Moldable Surface Hardened Explosive, is stable enough that the force required to detonate the bullet can only be generated by an impact while in flight; thus, the ammunition cannot be unintentionally detonated by dropping a round, magazine, or loaded gun.

Because the M41’s ammunition makes it unsuitable for use in many harsh environments, the similarly-sized M933P carbine is more frequently used, although in places like space stations and ships, where the weapon and its ammunition are less likely to come into contact with sources of contamination, the M41’s explosive-tipped rounds give it a significant advantage in firepower over the M933P, and equal range.


The M41’s carrying handle has a deep groove running down the center of it, which accommodates both a front post sight and a rear peep sight. The elevation of the peep sight is very similar to that of the rear sight used by the M1 Carbine, with a sliding ramp used to adjust for elevation at fifty, one hundred, and two hundred meters. The sight is also windage adjustable by a small dial underneath the ramp assembly that moves the entire sight to the right or left. Additionally, an M86A1 Close Quarters Optic red dot sight can be used. This modification of the M86 red dot sight clamps onto the carry handle and is useful at close ranges.


The M41 is fed from a thirty-round double-stack double-feed box magazine. Several experimental designs with higher capacities were attempted, including one highly unconventional U-shaped design that carried ninety-nine rounds. This design failed because it was considered to be too long, too wide, and excessively heavy, as well as having miserable reliability due to issues with the square ammunition turning the 180-degree curve at the bottom of the magazine. The weight distribution of the wide magazine was even bad enough to unbalance the entire weapon. The thirty-round magazine has remained the only magazine accepted by the US military for use with the M41.

Additional Accessories:

Although promotional and recruiting posters for the Colonial Marines frequently depict M41s with the U1 underbarrel grenade launcher mounted, this weapon is only issued to infantry fireteam leaders. It provides an important boost in firepower but the extra weight of both the launcher and the grenades, as well as the resulting lower number of magazines for the gun itself that a user can carry, mean that it is not practical for every Marine who uses an M41 to have a grenade launcher fitted to it.

However, the M41 can also be fitted with the U7A2 underbarrel shotgun, a straight-pull bolt-action shotgun which holds two rounds in the magazine and a third in the chamber. And while the M41 cannot directly mount a bayonet to the barrel with a conventional bayonet lug system, a third option is a bayonet that slides onto the mount rail for the U1 and U7A2, with a ring mount long enough to fit over the flash hider.

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