Few areas on a modern vehicle provide much protection from modern ammunition. Beyond the engine block and possibly the wheel wells, modern vehicles do not feature sufficient materials of the needed thicknesses to reliably stop an incoming bullet, regardless of caliber. That said, given the choice between having nothing between an incoming round and something, something would be preferable. But that assumption is based on inferences rather than ballistics tests.
Cover Versus Concealment
Discussions on using parts of cars to defend from incoming bullets need to clarify the difference between concealment and cover. Concealment is anything that may obscure your exact location but is unlikely to significantly protect you from incoming bullets. Cover is any obstacle between you and incoming bullets that would result in stopping those bullets.
What constitutes cover versus concealment will vary based on the caliber and type of bullet an attacker fires at it. For instance, a wall that can reliably stop a 9mm handgun bullet would be cover for that particular round, but if that same wall is easily penetrated by a 7.62x39mm rifle bullet, it would only be concealment for that round. Cover is usually also concealment, but even this can change, such as when the cover is transparent bulletproof glass.
Anyone who has had the opportunity to either shoot a vehicle or examine a vehicle that has been shot will quickly realize car doors and other areas outside of the engine block vary wildly in their ability to stop a round. The type of round, the angle of impact, whether the bullet encounters internal mechanisms, and the window being up or down will all change the success or failure of a car door stopping or significantly slowing an inbound bullet. I have seen car impacts of 9mm and .45 ACP that have failed to penetrate, and I have also seen .22 Long Rifle that penetrated with no issue.
The Bonnie and Clyde death car is often cited as an example that even an older, heavier car is no help against incoming bullets. Six law enforcement officers fired more than 150 rounds into the outlaw couple’s Ford V8, hitting each of the criminals multiple times with fatal wounds. What is lost in this example is that of the 112 penetrations of the vehicle, most of those were likely fired from the officers’ rifles.
I have commonly given the advice that the engine block is the only reliable cover on a modern car and that all of a vehicle’s other areas are little more than concealment. But I like to base my recommendations on real evidence. Although there are plenty of suppositions made based on ballistics and materials — and many more examples based on direct observations — I could not find much in the way of controlled ballistics tests. Therefore, I set out to put a modern car door to a controlled test, specifically addressing two questions: Will a 9mm defensive round reliably penetrate a car door when it’s shot directly into the surface? And if it does reliably penetrate, how much energy (penetration) on average is lost as it passes through?
The Car Door Ballistics Experiment
The goal of the exercise was not to examine multiple car doors across multiple calibers fired from multiple guns — although that might be a worthwhile experiment for a later date. Instead, my goal was to place as many controls on the testing as possible to come up with a consistent answer as a baseline. Thus, I kept each element consistent throughout the experiment.
I used a Glock 19X loaded with defensive ammunition and fired, from 10 feet and straight on, into a Clear Ballistics 10 percent gel block with and without a 2012 Chevy Cruze front-driver’s-side car door in front of it.1 I used Speer Gold Dot 124-grain 9mm hollow-point bullets designed specifically to expand on impact. I measured velocity with a LabRadar chronometer and calculated ballistic penetration by examining the length of penetration in the gel blocks, which were 16 inches long, 6 inches wide and 6 inches high.
I measured rounds from the Glock 19X for consistent average velocity and penetration at exactly 10 feet — with no intervening objects — and then fired again with a new block of the same ballistic gel, still at 10 feet, with the Chevy Cruze car door directly in front of it (about 2 inches shy of 10 feet from me). I selected a section of the door with a metal exterior and interior (about 50 percent of the door featured both interior and exterior metal), avoiding thick plastic materials, the window and mechanical devices. I also selected this location because it would be approximately where a driver’s center mass would be. I shot each round within 1 inch of the other impacts in a 6-by-6-inch area.
I fired 10 rounds into the Clear Ballistics gel block with no intervening car door. The rounds were consistent in their velocity, ranging from 1,075 to 1,115 feet per second across all 10 rounds fired. Additionally, the ballistic gel penetrations were consistent when the car door wasn’t present, with each round flowering from 0.357 inches to 0.5 inches and stopping — intact — at 12 to 15 inches into the gel, providing a baseline of what happens ballistically in the absence of concealment or cover.
The results of the bullets fired through the Chevy Cruze door proved to be less consistent. Although the velocities of the bullets prior to impact with the car door were very similar, contact with the door had significant influence on the bullets after that.
My first question was clearly answered, as all 10 rounds successfully penetrated both metal walls (exterior and interior) of the door. The initial holes punched in the exterior metal of the car door were the expected size (0.357 inches across, with no detectable variation). However, the interior holes varied from 0.357-inch round holes to more-irregular holes of approximately 0.5 inches.
These changes were further highlighted in the ballistic gel. Of the 10 rounds fired, none of the rounds flowered or expanded and only showed slight warping. These rounds also greatly varied in their penetration, ranging from 5.5 to 17.5 inches into the gel. On average, the bullets with only minor deformation (the bullets had not flowered) penetrated further than bullets that had not punched through the car door before hitting the gel.
In addition, all 10 rounds fired through the door projected fragments of the door metal into the gel. These metal fragments penetrated between 0.5 inches and 5.5 inches, with more than 70 percent having reached 2 inches or less.
Results
I went into these tests with an assumption that a bullet would lose some of its ability to penetrate a gel block if it penetrated a car door first. To my surprise, the data suggested that Speer Gold Dots fired directly through a car door are, in fact, more penetrative than expected. This is likely due to the impact with the door defeating the design elements intended to facilitate petaling.
So, conventional wisdom tells us that on most modern cars, there are only a few areas that will reliably stop an incoming round. This test of that wisdom provides additional evidence that it is correct. The data indicates that contrary to initial assumptions, a jacketed hollow-point passing through a modern car door results in greater penetration, as the impacts prevent the bullet from properly deploying.
The evidence clearly shows that car doors not only do not provide cover but also may actually make incoming rounds more injurious. Every round that penetrated both the exterior and interior metal of the door failed to deform as designed, penetrated the gel deeper than if there were no barrier, and resulted in fragments of the door penetrating the block as well.
In short, it is clear that a car door does not provide cover from a 9mm defensive round. Furthermore, it may even be worse than nothing in some ways.
This controlled, real-world test suggests that bullets do not just shoot through a car door unaffected but rather penetrate in such a way that, if directly striking the door, will penetrate further and generate additional fragments from the door itself. Although the engine block of a car can be a useful source of cover, the tactical value of the rest of the vehicle is further thrown into question by the results of this experiment.
Results of Ballistics Testing
Endnotes
(1) The author wishes to thank B&B Auto of Bloomfield, Indiana, for donating the 2012 Chevy Cruze and Clear Ballistics for providing the ballistic gel.
Sources
Clear Ballistics: ClearBallistics.com
Bonnie and Clyde’s Death Car
On the afternoon of April 29, 1934, the notorious criminals Bonnie and Clyde stole a cordoba gray Ford sedan from the home of Jesse and Ruth Warren in Topeka, Kansas. Clyde Barrow had a particular admiration for Ford automobiles and had even written a letter to Henry Ford praising the company’s cars just two weeks prior.
“While I still have got breath in my lungs, I will tell you what a dandy car you make,” he told Ford. “I have drove Fords exclusively when I could get away with one. For sustained speed and freedom from trouble, the Ford has got every other car skinned and even if my business hasen’t been strickly legal, it don’t hurt anything to tell you what a fine car you got in the V8.”
Bonnie and Clyde put approximately 7,500 miles on the stolen Ford sedan before their fateful encounter with law enforcement in Louisiana on May 23. Following their deaths, the Warrens engaged in a legal battle with Sheriff Henderson Jordan to regain possession of their bullet-riddled car. Eventually, Ruth Warren sold the vehicle to carnival operator Charles Stanley for $3,500 in 1940. The car then embarked on a tour across the United States, changing hands multiple times along the way.
In 1988, the owners of Whiskey Pete’s Hotel & Casino, located in Primm, Nevada, purchased it. Visitors to the casino had the opportunity to view the iconic car where Bonnie and Clyde met their end. However, in December 2022, the owners of the casino decided to relocate the car to Buffalo Bill’s Casino Hotel. Today, patrons of the casino can try their luck on one of the Bonnie-and-Clyde-themed 25-cent slot machines while sitting in front of the infamous vehicle.
— Frank Jastrzembski, Contributing Editor
