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Marvin Heemeyer’s Armored Bulldozer

United States of America (2004)
Improvised Fighting Vehicle – 1 Built

A one-man rampage

In 2004, the resort town of Granby, Colorado was terrorized by a man named Marvin John Heemeyer. A costly amount of property and vehicles were destroyed by a single man and his retrofitted Komatsu D355A bulldozer. Heemeyer’s bulldozer (also known as the Killdozer) was an engineering marvel for a single man and managed to take explosives and armor piercing ammunition. Not much is known about the man, but he claimed to be influenced by God. He recorded himself prior to the rampage explaining his motives and his targets. However, even though the recordings were released to the news reporters, they were never fully released to the public. Only bits and pieces can be found online.Heemeye's Killdozer at the end of its rampage
Heemeye’s Killdozer at the end of its rampage


Marvin John Heemeyer (born in South Dakota, October 28,1951), a successful welder, owned two muffler shops named “Mountain View Muffler” in Granby and nearby Boulder, Colorado. He was known by the town for fighting civil issues such as a failed proposal to bring gambling to Grand Lake, Colorado (where he lived) in 1994.
The town of Granby allowed a cement plant to be located near Heemeyer’s muffler shop in 2000. This angered him over the noise, dust and the limited access to his shop it could create. Heemeyer tried to convince Cody Docheff, the project’s operator, to sell his property, but ultimately failed.
In 2001, the town sided with the concrete plant. Heemeyer countered this with a lawsuit which failed again.
In 2003, he found himself involved in another conflict with the town concerning whether he should be connected to the town’s sewage system. Heemeyer was not part of the system. He was forced to pay the $2500 fine and wrote a check which he enclosed the note with “cowards” written on it.
He plotted his revenge. This involved his Komatsu D355A bulldozer. He had originally purchased it to construct roads to his shops. In March of 2003,, Heemeyer deeded his house to a friend and lived in his shop. He then sold off both of his shops and the building that housed his bulldozer.
However, he kept 185 square miles (479 square kilometers) of closed off land with a building where the bulldozer was moved to in December the same year. For six months, he used his welding skills to armor up his bulldozer so he could use it for his revenge.


The default 49 ton Komatsu D355A bulldozer is powered by a 410 hp (305 kw) engine. It had a top road speed of 7.45 mph (12 km/h) and a horsepower per ton of 8.36. Heemeyer’s armored version brought the weight up to 61 tons. This most likely slowed the bulldozer somewhat and decreased the horsepower per ton to 6.7.


The bulldozer was armed with a .50 (12.7mm) Barret M82 semi-automatic rifle at the rear, 5.56mm FN FNC semi-automatic assault rifle at the front, and a .223 (5.7mm) Ruger Mini-14 at the right. His two side arms were a .357 (9.1mm) Magnum revolver and 9mm Kel-Tec P-11. These weapons were fired from small firing ports inside the cabin.

One of the Killdozer's weapons, a Barret M82 rifle
One of the Killdozer’s weapons, a Barret M82 rifle


The armor consisted of two half inch (12.7mm) steel plates with concrete in the middle and bonded plexiglas which gave it the same benefits of composite armor. This proved very effective against small-arms fire, armor piercing ammunition and grenades.
The cameras which allowed Heemeyer to see his surroundings were connected to three monitors and protected by three inch (76.2mm) bulletproof plastic. The armored Komatsu D355A bulldozer also had a sophisticated air filtration system and air conditioning system.


On June 4, 2004, Heemeyer greased up his bulldozer to make it harder for people to climb on top before he bolted himself shut inside. He smashed through the building that housed his bulldozer and proceeded to his first target which was unsurprisingly the cement plant near his former business.
While this factory was being destroyed, the owner, Cody Docheff, drove one of his own construction vehicles to try and stop the destruction. Heemeyer saw this and quickly charged towards Docheff’s vehicle. Docheff regretted his decision. His vehicle was not big enough to stop the bulldozer so he tried to make his escape by driving away. Heemeyer rammed the rear of Docheff’s vehicle.
The armored bulldozer preparing to rip through a building
The armored bulldozer preparing to rip through a building
During his rampage, he managed to destroy a local bank, his former business, hardware store, the town hall, the police department building, the home of Granby’s deceased former mayor, the town’s library, local newspaper office, former judge’s home, and an enormous amount of cars. He spent a few minutes trying to ignite the Independent Propane Company’s storage tanks by firing at them with his .50 cal rifle. Luckily, they did not explode or catch fire.

Marvin Heemeyer’s armored bulldozer reconstitution by D Bocquelet


After being sealed by an industrial loader inside a group of buildings, Heemeyer in his armored Komatsu bulldozer tried to escape by ramming through buildings. The chaos stopped when the bulldozer collapsed inside a store’s basement.
Police officers charged towards the bulldozer but it was covered with grease which made it tougher for them to get on top of the machine. Colorado’s governor considered using the Apache’s Hellfire missiles from the Colorado National Guard to destroy the vehicle, but it was already bogged down inside a basement. Heemeyer committed suicide with his .357 (9.1mm) Magnum revolver. His armored bulldozer was stuck. He could see no way out and he did not want to go to jail.


Fortunately, there were no civilian or police deaths, however, Heemeyer had caused seven million dollars of damage to buildings and vehicles. It is said that killing civilians wasn’t his intentions, but his tape recordings say otherwise. Heemeyer’s recordings were released by the police department to news stations, however, only bits and pieces can be found online. It took twelve hours with a blowtorch to enter into the cabin of the armored bulldozer to retrieve his dead body.
The town hall after the rampage This truck was one of the many vehicular victims of Heeymer's rampage
The incident left 7 million dollars worth of damage.
Heemeyer is seen by most as just a terrorist, but some see him as a patriotic American for standing up to the government. C4, grenades, and more than 200 bullets were used against the bulldozer and had little to no effect. A few people in Granby proposed a yearly celebration of the incident to generate tourism. The idea was rejected, and the armored bulldozer was scrapped.
Luckily, insurance and state aid came to help the ravaged town of Granby and it quickly got back onto its feet. After Heemeyer’s rampage, it received the reputation as the “Killdozer”. Funny enough, this isn’t the first kind of attack in Colorado. In 1998, a man named Tom Leask conducted an attack with a government owned front end loader in Alma, Colorado. He managed to destroy the town’s post office, town hall, fire department, and water department until he was taken into custody.

Similar Vehicles

Armored bulldozers are nothing new and are present in many conflicts as professionally manufactured or improvised combat vehicles. This bulldozer is particularly interesting due to how well it protected him from C4, grenades, and armor piercing ammunition. Plus, it only took one expert welder to make this impressive contraption.
The Israeli Defense Forces has different armored versions of the D9 Caterpillar with slat armor and a protected cabin; other examples include the British Centaur bulldozer, Japanese Type 75 bulldozer, American D7G Caterpillar bulldozer, armored bulldozer used by the Sri Lankan Armed Forces in Sri Lanka against the LTTE (Liberation Tigers of Tamil Eelam), and dozens of other bulldozers.

An article by Joshua Martinez


Suburban Legends: True Tales of Murder, Mayhem, and Minivans
The Colorado Mountain Companion
Komatsu D355A-1 specifications
News article about the event

Killdozer specifications

Dimensions TBA m (TBA)
Total weight, battle ready 61 tons
Crew 1
Propulsion Komatsu SA6D155-4A, 410 hp
Armament .50 (12.7 mm) Barret M82 semi-automatic rifle
5.56 mm (0.22 in) FN FNC semi-automatic assault rifle
.223 (5.7 mm) Ruger Mini-14
Armor Plexiglass, Concrete, .5 inch (12.7 mm) steel plates



A good shot of the bulldozer after the destruction spree
Various shots of the KilldozerVarious shots of the KilldozerVarious shots of the Killdozer

47 replies on “Marvin Heemeyer’s Armored Bulldozer”

The driver of the other bulldozer wouldn’t have had a chance against a Barrett light fifty, also known as a anti-material rifle used to take out light armored vehicles. Which happened to be Mr. Heemeyers main weapon.

Armor on killdozer was said to be upto 15mm to 30mm thick equivalent and a mix of concrete and steal.. im not sure a .50 can pen that especially if angled.. most .50/cals will be lucky to get through 15mm. I cant find much info on the specific weapon you’ve listed however.

I think he was talking about the driver of the counter-killdozer bulldozer since it wouldn’t have had 18 months worth of construction of an armored casing around it and the .50 was pointed forward on the killdozer so another bulldozer without the armor trying to stop him, he could have easily just shot the other driver and drove off.

His ripper was in the way so anything he tried to shoot would just get deflected by the ripper. i was there that day and because my dad was county commissioner I was able to go see it after the fact. I do remember the cops looking for a 50 cal to attempt to stop him. they finally found one.. the guy who had it was on his way into town but that was when Marv got hung up in gambles

I believe that they used another dozer in hopes of flipping him, but he shot at the driver and he backed off.

Clark Branstetter was the head of road and bridge , he took 2 scrapers and tried to stop Marv… had one of those scrapers were fully loaded he would have been able to stop Marv, apparently the damage to both the scrapers was significant. then 2 lowboys were destroyed when attempting to load the dozer. the county blew a shit load of money on their own mistakes.. pretty fun day tho

Cody Docheff piloted a front end loader against the Heemeyer’s heavier bulldozer. He was unsuccessful. Heemeyer fired a few rounds into the bucket of the front end loader which made him back off permanently. He also later encountered a belly scraper by a random person but that too didnt work.

People feel government is to big and eating our lives. Regulars protests are nothing for regular people only if some domestic terrorist like Soros sponsors them to get they agenda moving. He’s a patriot and show everyone how government frustrating citizens. .no he was not terrorist by no any means . People should stand up agaist corruption and government bullying.

If you want people to understand what your saying you have to be able to read and write, whatever your point was it’s lost now because you can’t write or construct a sentence properly. Also based on what I think you were trying to say I’d request that you keep the ignorance on the inside of your head because it seems to be leaking out and nobody want to get that stuff on there clothing because it stains and possibly causes cancer of the brain. Thank’s “Dimwit Danius”
P.S. please for the sake of humanity don’t reproduce, doubt thats a possibility for you but still

You have no business calling out anyones grammar and spelling. Dear lord, yours is atrocious as well.

first thing i thought when i first seen it on tv is ”man all they got to do is buy a $10 tarp and cover it he wont be able to see

Well, if you watch the video, the police are walking pretty close to it. It could definitely be done

Yes I like Zacks idea, if they had of rushed down to the hardware before it got destroyed and brought a few cans of paint and threw it. He would have been limited to driving randomly at whatever building came next.

If he would have produced multiples and brought them down into the Denver metro area he could have sold as many as he could make.

He got his revenge by destroying the businesses of the people who destroyed his business by blocking off his road access then demanded he connect to the city sewer, but the owner of the cement plant refused to allow the needed digging across his property.
So the bunch of a-holes who decided to run Heemeyer out of town reaped what they’d sown. The UK celebrates Guy Fawkes (despite his failure) so why not celebrate Marvin Heemeyer for standing up to government corruption?

If I recall correctly Guy Fawkes Night is not celebrated in commemoration of Fawkes and his compatriots. But rather to celebrate that they failed in their plot against parliament and were subsequently executed, hence why effigies of Fawkes are burned on bonfires.
TE Moderator

Not entirely, you’ve got to remember that people back then still held pagan beliefs. this being a christian government wanted none of that, so all the pagans could do what band around this one defiant act. Of coarse you won’t find that in most history books, but the older ones always paint a more colourful story

Heemeyer sold the land the cement plant was built on in the first place, for about 5 times what he paid for it although he tried to back out and get even more. He sold it with no easement and then still kept using it to access his remaining property which was adjacent to it. This worked for a while because the zoning was not correct for a cement plant which delayed construction but once zoning was changed and the plant was actually built his access went away and he threw a tantrum. He bet on the zoning change being denied, and getting away with continued use of land he no longer had any right to use, and he lost. He created all his own problems by selling the land the plant was to be built on with no easement to preserve his use of it for access. He was no victim.

They should’ve just poured gasoline on it and then tossed a lit match on it. The armor shell would’ve acted as a heat sink, trapping Heemeyer in a practical oven.

They tried that its in one of the videos the construction of the concrete plant cut his sewer line that is what caused the fine which is strange you would think they would have to relocate it looks like the town just wanted the land and did every thing possible to take it from him if I had the money I would buy a HSC D-9 and settle a few scores LOL The US military actually went to Granby and examined that dozer to see how he made the composite armor .

all that needed to be done was trip up the skids. jam something up in one them and it would stopped made the dozer useless

I debated this with my friends, one of which owns and FNC, and no, that’s an FN FAL in .308, not an FNC. The FNC has a charging handle and the stock is different.

Oh so you run rampant in colorado with a giant bulldozer armed with firearms even a .50 cal and T H I C K armor because your angry? interesting enough. Nice idea tanks encyclopedia

SHEEEEEEEEEEEEEEEEESH last comment was last year Xd, but I am grateful to know this website is a thing. very useful

So I’ve been doing my best to research this incident, and ran across a curious co-incidence. The day of the Killdozer rampage is the same day of the Tiananmen Square Massacre in Beijing,China, exactly 15 years later. 20th and 35th anniversaries, respectively, coming up this year.

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