What Happens When You Shoot a Car With Frangible 9mm Ammunition? [VIDEO]

Frangible ammuniton vs car
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Most frangible ammunition is made by compressing copper powder (either pure or with tin and/or polymer added) into the shape of a bullet on a machine basically identical to the kind used to manufacture medicine tablets. When a frangible round hits something hard — a steel plate, a rock, etc. — POOF! It transforms back into dust.

But just how easily does that happen? Does frangible ammo return to dust if it hits something like a car door? A window? A tire?

To find out, Nick and I hit the range with a box of Sinterfire 9mm and a garden variety GLOCK 19. The results surprised both of us.

If you’re at work or just don’t like watching videos, here’s the spoiler:

The frangible 9mm zipped through one car door, through the door card, through the other door card, and — sometimes–  exited the door on the far side of the car. The bullet shed copper the whole way — it entered the first door at 9mm and exited the second one at maybe 4mm…who knows? But it appears to have stayed quite deadly the whole way.

A frangible round zipped through the trunk and through the rear seat, with a couple of small chunks remaining in tact enough to puncture its way into the front seat.

Another one made it through both sidewalls of a steel-belted radial tire and punched through the plastic wheel well liner.

One made it right through a cast aluminum valve cover. What it did inside there or how much solid projectile was left, if any, after breaking through, we don’t know.

Interestingly, the frangible 9mm didn’t like vehicle glass. Even shooting at the pre-fractured safety glass of the rear window, the bullet was reduced mostly to dust and possibly a few chunks, though the damage we saw from “copper chunks” could have been caused by flying glass, too.

Laminated windshield glass also appeared to mostly destroy the projectile. At least, it certainly turned much of it into dust. Certainly more than the sheet metal did.

So there you have it. Once again, we find that a car provides concealment, but not cover unless you’re behind a solid chunk of metal like the engine block, hubs/brakes, etc. Even if you’re facing frangible pistol ammo.

Nick and I were surprised to see this kind of ammo pass completely through two car doors. We wouldn’t have guessed that a pane of automotive glass, whether a window or a windshield, is actually better at turning a frangible projectile into dust than steel body panels, but there you go.

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  1. I’m not suprised at any of this. Frangible ammunition was meant to turn to dust on ballistic steel plate targets. Not the light weight sheet steal, even aluminum, that vehicles are made of today. My Dad’s ’56 Chevy would have probably been a different story. The bottom line is, if a projectile exits a muzzle, assume it’s deadly.

    • Hmm. I haz to wonder what type of ammo Air Marshalls carry. A single errant bullet isn’t going to take down an entire plane, but nobody wants to puncture an aluminum fuselage that’s traveling 600mph at 38000 ft altitude.

      • Haz, last I heard they were carrying SIG 226 in .357 SIG in some 125 grain HP. Theory being at the time that a light, high velocity round wouldn’t be as likely to penetrate the fuselage. I told a couple of those guys, “You should shoot those guys in the head with the largest caliber handgun you can get your hands on. Damn the aircraft.” Just me. It won’t take but once and that shit will be over. Aircraft takeover ended over Pennsylvania on September 11, 2001 anyway. Even they know that.

        • Explosive decompression isn’t a thing that’s going to happen in a modern passenger aircraft because of handgun rounds puncturing the fuselage, not even if the Air Marshals are blasting away with .50AE Deagles two-fisted John Woo style. I would be a lot more worried about holes in the pilots than holes in the aircraft.

      • That’s a many times busted myth, although I don’t know if by The Myth Busters. Unless there’s a full-scale shootout at the OK Corral with dozens of cowboys, the plane is safe.

  2. As I understand it, automobile glass is actually a set of layers of different materials. I do know that auto glass is designed to fracture in such a way so as to not leave any sharp edges; I’ve experienced this during an accident. Maybe the different densities is what causes the round to turn to dust.

    • pcb, you’re not far off. Windows in vehicles are tempered safety glass, with the exception of the laminated windshield. The safety glass is designed to break in such a way as to reduce the chance of severe lacerations. Watch not Bruce Willis Christmas movie. That laminated windshield is tough. Two layers of glass with some kind of a synthetic layer in between. It will make 55 grain M109 ball act like frangible ammo. BTW, window tinting on the tempered safety glass can act like a poor man’s laminated window. Concealment, no window is cover. I don’t care what they say, I’m ducking.

  3. Yeah, frangible ammunition will pass through light weight sheet steal and aluminum. Its not made to be ‘frangible’ for light weight sheet steal at close range. So this is not surprising really.

    A window a windshield is a different matter as the ‘safety glass’ material structure is made to be more energy absorbing and deformable before it collapses at a specific point. Basically, the remaining energy in the instance has to go some place (Newtons law) and it results in the frangible bullet turning to ‘dust’ (mostly).

    • Hmm…what about soft(spire)point 223/556 ammo? Is it really “safer” to defend my home with it or will it enter my neighbor’s hasienda? No bueno???

      • former, those are very good questions and concerns. I was lucky enough to participate in an a couple of tests with Federal/CCI/Speer. We shot everything three ways from Sunday. At, through and into everything. You want something that works everytime? There is no such thing. Choose a bonded core bullet in whatever caliber you prefer. They tend to have the expansion and penetration I’m looking for.

  4. Whether or not a frangible bullet will disintegrate is probably a huge function of the bullet entry angle relative to the target surface. If those frangible bullets hit glass at an oblique angle, they may very well deflect and turn to dust–and do the very same if hitting a sheet aluminum or steel door at an oblique angle.

    • uncommon, that’s a good point. One I had not thought of. Frangible ammunition is meant to hit steel targets point on.

  5. It would be interesting to see what happens to prefragmented bullets like glazers and magsafe when they hit an automobile

    • “What happens to frangible bullets when they hit a human body?”

      They fragment (Duh).

      The real question is, just how big of a mess is it for the surgeon to clean that crap out of the wound…

  6. What does this say about how good that 50 or 60 thousand dollar vehicle is when ‘the glass’ portion of the exterior is the strongest part?

    • Nothing of relevance. The average car isn’t designed to be bulletproof, the loads it’s designed to take come from much larger and more massive objects moving at much slower velocity – and to sacrifice itself to protect the occupants. Very small, fast and light impactors are something outside the design scope of a car, especially when most of the exterior surface area of a car is only there for environmental isolation or stylistic looks, with the structural reinforcement underneath designed to spread out the loads of the larger objects’ impact (providing more and stouter material to slow down a bullet) comprising a relatively small portion.

      • I was referring to ‘in general’. I’m not looking for the ultimate bullet proof car.

        Many car body parts are glued together.

        • “Glued” with automotive/aerospace structural adhesives, not the goo from the sort of Elmer’s glue sticks elementary school teachers need to keep bored, hungry students from eating in class.

  7. Frangible bullets are billed as penetrating less than non-frangible bullets. The basic theory is because after the bullet comes apart the remaining individual pieces have less weight and therefore less momentum energy to drive them through, in this case for this article, relatively thin steel sheet.

    The key words here, often over looked and ignored, are “after the bullet comes apart” and specifically the word “after”. In other words frangible bullets penetrate less AFTER they start to disintegrate, and not before. People expect them to completely disintegrate on impact and not penetrate other than what they hit first but they really don’t do that completely even though on some targets they may begin to come apart. And what we are dealing with here is energy in a focused point (the point of impact).

    For the physics involved, basically; The point at which that ‘disintegration’ happens or begins to happen in terms of penetration depends on, by the physics involved, basically, the ‘target’ material and its energy absorbing and deformation properties in relation to bleeding energy from the round AND the energy driving the round (causing momentum).

    So for example, as the basic theory goes, a whole frangible bullet could have the necessary energy to penetrate a target upon initial impact but AFTER entering not enough energy to exit or penetrate another surface beyond the initial impact surface because it has disintegrated or is beginning to disintegrate. BUT…. doing that depends on the ‘target’ material and its energy absorbing and deformation properties in relation to bleeding energy from the round AND the energy driving the round (causing momentum).

    Thus for what happened in this article demonstration we saw the physics at play, basically; Straight on shots at close range on what is sheet steel type material didn’t allow enough energy to be bled off, the first impact material and the material behind it didn’t have the necessary energy absorbing and deformation properties to cause the round disintegration action pieces remaining to happen completely enough to prevent further penetration from what was left of the round. Where as, as the article mentions, there was a lot more fragmentation against the window/windshield ‘safety glass’ because it is built in such a way as to have energy absorbing and deformation properties against a focused point of energy and the sheet steel doesn’t have that capability.

  8. Next time tape a big black piece of paper to the outside of the door, then you wont have to work so hard to figure out if it went through.


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