Aliens M41A Pulse Rifle Vs. Alien: Romulus F44AA Pulse Rifle

The 2 Fictional Guns Compared, Plus The Real Tommy Gun & Shotguns Underneath

It’s one of the most iconic fake firearms in all movie history: the M41A Pulse Rifle that we all saw for the first time in James Cameron’s Aliens from 1986, one of the few sequel films that’s on par (some say better) than the original. The latest installment in the long-running Alien franchise, Alien: Romulus (2024) was a runaway hit at the box office, and the movie just hit streaming services with a 4K disc on the way.

There were a lot of awesome things about Romulus, but one of the best bits of fan service: not only is a version of the Pulse Rifle prominently featured, but it’s something audiences had never seen before. 

Cameron was famous for not only paying close attention to the firearms in his action movies but also being personally involved in their choosing. You can see a lot of that in the behind-the-scenes docs about Terminator 2: Judgement Day. But for Aliens, the filmmakers had to create a futuristic loadout used by Colonial Marines in space. To be in keeping with the original, the weapons couldn’t be too far out there — they had to be relatable. 

One of the reasons the blasters from the original Star Wars trilogy are so iconic is because they were made from real firearms as a base, mostly early European WWII vintage. Han Solo’s blaster is a Mauser C96. The blaster carried by all the Stormtroopers? It’s a British Sterling submachine gun. Part of the reason George Lucas did this was to save costs, but it worked on several levels and made them somehow recognizable. 

Cameron went the same way — literally. The M56 Smart Gun carried by two of the Space Marines in Aliens — think of it like an all-purpose machine gun mounted to a person — was a WWII-era German MG42 machine gun with the grip and stock removed.

It was then added to a real Steadicam harness and arm, which gave it some really cool, smooth movements on camera. Then, a bunch of cosmetic and practical motorcycle parts were added. The results were awesome. 

For the star weapon carried by most of the Marines and later used by Ellen Ripley (Sigourney Weaver) in conjunction with a flamethrower during the movie’s pulse-pounding final act after an unforgettable crash training session from Cpl. Hicks (Michael Beihn), the armorers started with an already iconic firearm: the Thompson submachine gun. 

You can clearly see the Thompson’s distinctive receiver, bolt handle, and grip angle in the final future-gun design, and the magazine even goes in the same place — it had to fire blanks on set after all. A custom aluminum shell is wrapped around the rest of the gun, shrouding the barrel and providing a large carry handle/iron sight rail on top. 

But the M41A isn’t just a rifle, it’s also a grenade launcher that fires small explosive shells that are about the size of a 12 gauge shotgun shell in the movie. That’s because, mounted beneath the barrel is a chopped-down Remington 870 pump action shotgun housed by the heat shield and foregrip from a Franchi SPAS-12 shotgun.

At the rear is a retractable, skeletonized stock that looks like it may also have been made from parts of a SPAS-12 heat shield. 

Fun fact: the housings of the rifles were painted brown so that, under the blue set lights, it would show up as olive green in the movie.

Only one M4A1 prop rifle from the movie had a working shotgun attachment — the rest were all broken down after the production ended. The surviving Pulse Rifle made another appearance in Alien 3 (1992). 

So what are the specs on this assault rifle/grenade launcher of the future? 

There has been a surprising amount of fictional info written about this weapon in compendiums and books about the Alien universe. It even has its own development history. 

According to people even nerdier than me, the M41A Pulse Rifle was designed by retired USCM Cpl. Jonathan LaForce as part of the Marine 70 Program, which was established to procure a replacement for the current standard issue weapon, the Harrington Assault Rifle. The new weapon was based on the Harrington along with the Weyland Storm Rifle. LaForce built the prototype in his own workshop and it was selected as the winner of trials for a new service weapon in 2171. 

Early production models of the M41 Pulse Rifle had stoppage problems; it was later determined that substandard 10x24mm caseless ammunition was the cause, however, the Pulse Rifle took the brunt of the bad reputation generated by these early problems, especially following a disastrous incident on LV-832 when jammed pulse rifle cost many lives. 

If you know anything about the history of the M16 rifle in Vietnam, you know where this story came from. 

Design changes were made to quell fears, including the addition of cooling vents and other improvements, and it was issued as the M41A. It has served as the primary weapon for Colonial Marines ever since and has built up a strong reputation in that time, just like the M16A1.  

M41A Specs

Action: Electronic pulse firing mechanism
Fire Control: Trigger and battery pack in carry handle (10,000-round charge)
Select Fire: Semi-auto, 4-round burst, full-auto
Bolt: Rotating breech lock
Outer Casing: Titanium Aluminide Alloy
Internal components: High-impact, high-temp resistant polymers
Electronics: Hardened against TREE and background radiation
Weight (unloaded): 3.2 kg 
Weight (loaded): 4.9 kg
Barrel Length: 24.7 cm
Recoil Dampening: Reduces felt recoil and muzzle rise
Charging Handle: External, nonreciprocating, right side
Capacity: 99-round standard U-bend conveyor magazine
Ammo Display: Digital LCD Round Counter
Sights: Integrated groove sight in carry handle with adjustable rear sight leaf
Stock: Spring-loaded, extendable

Ammunition: US M309 round 
Caliber: 10×24mm 
Type: Caseless
Bullet: 210-grain, steel-jacketed, explosive-tipped
Propellant: Rectangular propellant block of Nitramine 50

Underbarrel U1 Grenade Launcher
Capacity: 4 rounds
Action: Pump

The F44AA Pulse Rifle from Alien: Romulus

While the guns in Aliens were service weapons carried by Colonial Marines, the version we see in Romulus is more “Use In Case of Emergency” weapons stored in a small rack on what is predominantly a science vessel. As such, they have features that make them a bit more user-friendly. 

When Tyler (Archie Renaux) explains how the weapon works to Rain (Cailee Spaeny), he calls it an F44AA Pulse Rifle. I choose to think of it as the civilian/commercial version of a military weapon, or possibly an experimental model. 

The housing of this weapon is predominantly white and it seems to have a shorter front end. While it seems to have an additional barrel and pump, there is no grenade launcher on this one. Instead, that space is occupied by a flashlight integrated into the handguard and presumably some kind of camera and sensor for the aiming system. 

Speaking of, the “AA” in the name stands for “assisted aim,” the gun’s biggest difference from the Pulse Rifle we know. An assisted computer aiming system can be activated that initiates an LCD targeting screen and target tracking that controls a mechanical stock that braces the shoulder and pivots to literally point the gun at a target when the user pulls the trigger half way — like aim assist in a video game, but far more dangerous. 

The F44AA also includes a familiar LED ammo counter on the side, which uses bars instead of numbers — and it apparently has a 400-round capacity. 

Now, Tyler says the guns are what Colonial Marines use, but some material says these pulse rifles are experimental models just used on the station, which would explain the different naming conventions. 

Since this movie takes place 30 years before the events of Aliens, it does make one wonder why such an advanced weapon would be seemingly downgraded to the M4A1 decades later. But I have a theory. 

Any system on these future weapons, just like firearms today, has to be powered by a battery. And we know that they have the space afforded by that carry handle on top for batteries. I imagine a computer-assisted targeting computer, screen, and robotic stock use up a lot of juice, which is important because electricity is required to fire the caseless ammunition. 

Pulse Rifles with these bells and whistles are likely fine on a space station or at a base where extra batteries are plentiful and the rifles sit on charging racks most of the time, but for long-range missions on hostile planets, something simpler to save battery life for essential functions is probably warranted.

I could also see Colonial Marines not appreciating their rifle aiming for them — that’s what the Smart Guns are for. Also, the assisted aiming system is probably quite a bit heavier and more expensive per unit than a spring-loaded adjustable stock and a trained Colonial Marine — and Weyland Yutani is a corporation after all.  As for the 400-round mags versus the 99-round mags in Aliens — maybe the giant mags were as reliable, or the military ammo takes up a lot more space because it’s more powerful. Sounds good, right?

But even the fancy Pulse Rifle can’t help Rain too much. See, they’re on a space ship through the whole ordeal, and many people don’t realize this, but they had weapons aboard the Nostromo in the original Alien (1979). They even took them along when they went to examine the old crashed alien ship on the planet’s surface. So why didn’t they use them to fight the Alien on the ship? 

Two reasons. If they missed, a round could punch a hole through the hull to hard space and potentially destroy the whole ship if not only killing everyone inside. Second, if they didn’t miss, the acid blood that would result from shooting the alien would eat a hole through the ship’s hull, and they all die. After all, a couple of drops of the acid blood from the facehugger went through three whole decks before it stopped. 

So, the crew stuck to flamethrowers. That’s all they could do. 

The Marines on the surface of LV-426 in Aliens didn’t have to worry about that (they had to worry about rupturing the nuclear reactor though), but Rain on the space station with her F44AA certainly does, so being armed isn’t the advantage that it first seems to be — though she uses that Pulse Rifle to devastating effect with a little help from a disabled gravity drive. 

Next up is a new TV series set in the Alien universe: Alien: Earth, starring Sydney Chandler, Alex Lawther, and Timothy Olyphant. The eight-episode season is set to premiere in 2025 on FX. It takes place before the original Alien, so who knows what kind of weapons we’ll see.