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Romulus Proto Pulse Rifle: How It Fits With M41A Lore

By | Published April 24, 2024

Set halfway between Alien and Aliens, Alien Romulus introduces a prototype Pulse Rifle, the iconic weapon used by the Colonial Marines decades later. The M41A Pulse Rifle has a rich history from the Expanded lore of books and games, including an almost endless array of variants. In this article, find out how this Romulus prototype fits with the canon of the Colonial Marines and the M41A Pulse Rifle, and if there are any conflicts with it.

First Origins Of The Pulse Rifle: The Weyland Storm Rifle

Weyland Storm Rifle

The Pulse Rifle origins are tied to the Weyland Storm Rifle, already developed early in the 21st century. Introduced on September 10, 2024 (coincidentally the same year as Romulus is released), the Storm Rifle is notable for being the first rifle able to track targets from over 500 kilometers away. Although also an early prototype, it saw usage by off-world security forces, in the early days of space colonization. The weapon had a lot of electronic parts and had reliability problems. Although not present in the Prometheus movie (which takes place in 2093), the Weyland Storm Rifle was introduced in the Prometheus promotional materials released online.

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The Time Between Alien And Aliens

Colonial Marine Zula Hendriks with the Pulse Rifle

The Pulse Rifle as we know it did not exist at the time of Alien (in 2122), but it did pop up in some sources before the time of Alien Romulus (set in 2142). In the Aliens: Defiance comic series, the Pulse Rifle saw heavy usage by both Colonial Marines (founded in 2101) and the Weyland-Yutani security forces. Furthermore, it was used by the primary protagonist Zula Hendriks. Aliens: Defiance takes place in 2137, and it the inclusion of the Pulse Rifle is somewhat problematic, as most other sources say that the iconic Pulse Rifle was developed decades later. Alien: Isolation, the legendary video game set in the same year of 2137 does not feature the Pulse Rifle either.

M41 Pulse Rifle

M41 Pulse Rifle

A detailed backstory for the Pulse Rifle was provided in the Aliens: Bug Hunt anthology book ("Episode 22"), although the canonicity of the book is sometimes disputed. Developed by retired Colonial Marine Jonathan LaForce, the M41 was another predecessor of the M41A, but much closer to the final weapon. Although he lived a quiet life serving a BBQ cart, LaForce was able to put together one of the best weapons ever made. Being much more versatile and robust than the Weyland Storm Rifle, the M41 gained a lot of popularity among marines and went into production by Armat.

M41A Pulse Rifle

M41A Pulse Rifle held by Frost on the USS Sulaco

The M41 was taken into service by the Colonial Marine Corps in the year 2171. The weapon was soon upgraded to the M41A which solved some problems with the weapon jamming and overheating. This is the weapon we see in Aliens, which takes place in 2179. The M41A uses 10×24mm Caseless ammunition, although shell casings are often shown flying when fired, although this is just a movie mistake. The weapon generally mounts the under barrel U1 Grenade Launcher, but you don't usually want to mess with that.

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Lacrima 99

Lacrima 99 from Alien: Resurrection

The Lacrima 99, a successor to the M41A Pulse Rifle, became prominent 200 years after the latter's introduction. Although it differs slightly and wasn't developed by Armat, soldiers still refer to it as the "Pulse Rifle." The United Systems Military primarily employs the Lacrima 99, but it's also favored by mercenaries. This weapon shares the electronic pulse action mechanism of the M41A Pulse Rifle. While the Lacrima 99 cannot operate underwater, it functions when wet and features a lamp attachment below. It appears in both the film "Alien: Resurrection" and its related video game.

Romulus Proto Pulse Rifle

The Proto Pulse Rifle from Alien: Romulus

So where does the Prototype Pulse Rifle seen in the Alien Romulus trailer fit in? The movie is set 37 years before Aliens (in 2142), during the time that the M41A Pulse Rifle has not been fully developed yet (based on most sources, but not Aliens: Defiance). Regardless, the gun fits into the Alien timeline nicely and can be considered a prototype weapon developed by Weyland-Yutani in the secret Romulus lab on the Renaissance station. In appearance, the gun is light grey but already has the iconic red LED ammo counter on the right side. The handle on the top is wider, and a black wire runs along the right side of the gun, hinting at its prototype status.

Behind The Scenes

The prop of the Proto Pulse Rifle

Soon after the release of the Alien Romulus trailer, an image appeared online seemingly depicting the prop weapon used in the movie. However, it is not clear if this is an actual prop from the movie or a fan-made replica. This prop is missing an led counter (or it might be covered), and there is no cable running on the side, as seen in the trailer. In this close detail, the weapon somewhat resembles the Lacrima 99 from Alien: Resurrection.


The full extent of the Prototype Pulse Rifle's usage in Alien Romulus remains to be seen. We are yet to hear if it will use the Pulse Rifle's iconic popping sound, and see if it will be used to kill Xenomorphs. The inclusion of the Prototype Pulse Rifle in the Alien timeline is not a problem and a welcome addition to the "bridge" between Alien and Aliens. As Romulus will be more similar to Alien, perhaps its sequel will take more inspiration from Aliens, and feature the Colonial Marines in full force.

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