Rifles vs. Vehicle Engines

[heypete]

I came across a month-old news story today regarding a French commando raid on Somali pirates.

One line stood out: "A sniper disabled the engine of the get-away car, while another helicopter dropped off three French commandos who captured six of the 12 pirates."

This got me thinking a bit: I've seen various movies of vehicles being disabled after having the engine shot with a rifle (like in Black Hawk Down). It's not an uncommon theme.

How effective is a rifle (or indeed, any other firearm) at disabling a car engine?

Certainly, I can understand that having various components shot would eventually disable the car (like putting holes in the cooling or oil systems, nicking electrical wires, and so on), but I'm more curious about how effective an ordinary rifle* is at causing a more or less immediate cessation of engine function.

Indeed, this curiosity makes me want to find an old junker car (or four), a range willing to let me test this out, and rifles in a variety of calibers. However, my budget won't allow me to do this, so I turn to the forum in the hopes that someone has some knowledge on this topic.

* Of any modern, commercially-available caliber, including .50 BMG.

 

[dmftoy1]

My .308 will punch through a rifle block with no problems . . .to be honest I think that M855 in my AR will do the same . .an engine block isn't all that thick/tough unless we're talking old Early-Mid 50's Ford V-8s. So if you know you can punch through the block then it's just like deer hunting . . . can you estimate the appropriate spot to place a bullet (you're looking at sheetmetal) and CAN you place your shot.

I'd be curious as to how quickly a bullet would shut down an engine. I don't think you'd punch through the crank and even without oil and engine will run surprisingly longer than you'd think. (Maybe you should write Mythbusters .. .they seem to like gun myths. )

 

[heypete]

Hmm. I always assumed (perhaps incorrectly!) engine blocks were fairly substantial things, and not easily penetrated by bullets.

Having Mythbusters do a test would be ideal, as their tests usually tend to involve entirely unnecessary explosions, which makes things a bit more fun.

 

[Double Naught Spy]

If you can penetrate a cylinder, you can get the cessation you want. Similarly, hitting a major electrical component such as the computer, distributor, etc. can do it as well.

Otherwise, most of the hits are going to result in slower kills, just like with living animals.

As for range, with AP ammo, you have a much greater range than normal ammo, but I would not know how far. I will say this, we tested an engine (dontaed by a local junkyard) and found that NOTHING penetrates all the way through, not even .50 BMG API unless it is a glancing hit through a corner or edge. Engines have a lot of cavities for fluids, cylinders, and such and even if the round penetrates one wall, it then gets trapped inside and does not exit.

So basically, there is nothing magical. You are just breaking things in the engine. Like hitting the heart in any animal, the engine is housed in a body that does a decent job of shielding its actual location even though you have a good idea of about where it is. Even so, incoming shotings that should hit can be deflected away from the engine and may not damage it, but still may produce the desired stop, or not.

The most effective, sure way is to pump several rounds into it.

 

[dmftoy1]

An engine block is a big heavy chunk of metal . . .but it's typically cast iron or aluminum. Any type of military penetrator round will punch through an AR500 steel plate (3/8 thick) like it's butter at 100 yards . . . cast iron is MUCH easier to go through. I've got a 10 inch gong that is rated for all rifles at 100 yards (except 50 BMG) and I've made the mistake twice now (once with 8mm, and once with some old 30-06 black tip) of shooting it. I have no idea how much it would penetrate but they didn't even appear to slow down. I've got some softer 1/2 inch targets that a guy cut for me 15-20 years ago and even a 7.62 x39 punchs through it easily . .although it seems to shed it's jacket in the steel while doing it. (sort of strange)

FWIW.

 

[Dave P]

Take yer superduper sniper rifle, (308 should work, but why mess around - use 338 Lapua) align the crosshairs on one of the crankshaft mains, and let 'er rip. (your scope does have xray capability, in addition to red dot and laser, doesn't it???)

I think the engine would self destruct in a few revolutions.

 

[leadcounsel]

As others have said, engines are mainly iron, steel and aluminum. They are not hardened for armor purposes. Engines are also rather delicate and intricate machines that require all of the main pieces to work together - kinda like a chain where the engine relies on the weakest link. Break that link and the whole thing comes to a halt. The main portion houses pistons, cams, oil, coolant, gas lines, delivery, spark plugs, electrical wires, injectors, etc. Significant damage to any of these would likely cause the vehicle to experience a fairly rapid decrease in performance, power, speed and fail fairly soon.

Having shot thick iron, steel and aluminum plates with my .223, .308, and 7.62x39 and seeing that the metal doesn't even slow the round, I would suspect that large rifle rounds would penetrate deeply into engines or pass right through them, doing significant damage to the whole system.

The military shoots tires and engines to stop vehicles and it seems to work well.

It would be a hoot to find an old junk engine to experiement on or suggest it to mythbusters.

 

[squirrel sniper]

With any shot like that, your looking at more lucki than skill. Theres no way you can know wether it is going to be 4,6,8,10, or 12 cylinder. If it is front wheel the enigne would usually be sideways. Those shots are more luck that the bullet found something impotant than any actual skill. If you are trying to disable a car, your best bet woul be to shoot high at the front corner of the car so it will slide between the shock tower and the radiator and go over any exaust manifolds that might be there to take out either the timing component or the water pump on the front or hopefully make it into one of the cylinders.

 

[jmr40]

This is the primary role of the .50 BMG sniper rifle. Taking out vehicles, at long range. Using them on human targets is a secondary role.

 

[longrifleman]

http://www.theboxotruth.com/

Check out the Buick o Truth section. Very interesting. They weren't testing a running engine, but it won't be hard to extrapolate what would happen.

 

[Thin Black Line]

The military shoots tires and engines to stop vehicles and it seems to work well.

Typically, the turning of the conscious steering wheel and pedal pushing
operator behind the windshield into an unconscious non wheel turner and
non pedal pusher works better.

 

[Vibe]

A shot from above the vehicle, as in the usual type of sniper shot, would probably take out the carburator or fuel delivery system fairly easily, And the engine would stop pretty quickly at that point.

 

[dagger dog]

I think the best way to disable a vehicle is to shoot the driver. That would be the quickest, no doubt AP rounds in .30 cal will punch a hole in a cast engine block. BUT

I have seen an engine that had knocked a rod through the block leaving an enormous hole larger than a fist,then the rod snapped of at the wrist pin, the crank journal end fell into the oil pan, and the damn thing drove in for repairs,(customer was complaining of poor performance) I started it and drove it in the shop, no knocking no noise just a dead miss on one cylinder,I don't know how far the customer had driven it , this car was a subcompact Toyota Corolla with a 4 cylinder engine.This is just one incident of many hundreds of vehicles with "unrepairable or disabling" engine damage.

So if you think of a V8, my idea of reliable , would be nothing less than a cannon round 20mm at the smallest, or maybe multiple .50 BMG AP hits that can take out multiple cylinders at a time.

 

[R.W.Dale]

would probably take out the carburator or fuel delivery system fairly easily, And the engine would stop pretty quickly at that point.

As alluded to by another poster this almost EXACTLY like deer hunting in that you might take the crank position sensor with the first shot and bring things to a screeching halt OR you might just cause a bad vacuum leak in the upper intake tract and have a "wounded" car-animal that runs for awhile before expiring. What makes this more hit or miss with a car than a deer is unlike deer we don't know where the important bits are located on all models and cars don't wear their important bits nearly as close to their skin either.

I wouldn't even count on a busted engine block stopping a car immediately, with the limp home modes modern cars have you'd be surprised what they can run without.

 

[dagger dog]

I think the best way to disable a vehicle is to shoot the driver. That would be the quickest, no doubt AP rounds in .30 cal will punch a hole in a cast engine block. BUT

I have seen an engine that had knocked a rod through the block leaving an enormous hole larger than a fist,then the rod snapped of at the wrist pin, the crank journal end fell into the oil pan, and the damn thing drove in for repairs,(customer was complaining of poor performance) I started it and drove it in the shop, no knocking no noise just a dead miss on one cylinder,I don't know how far the customer had driven it , this car was a subcompact Toyota Corolla with a 4 cylinder engine.This is just one incident of many hundreds of vehicles with" unrepairable or disabling" engine damage.

So if you think of a V8, my idea of reliable , would be nothing less than a cannon round 20mm or many 50 cal AP hits that can take out multiple cylinders at a time

 

[Carl N. Brown]

Recently had problems with Ford and Chevy trucks (and before that a Nissan) and I must say, the vital parts of engines are in different places, depending on designer whims and fancies. Knowing where to shoot to do the most immediate damage is an obstacle. Even then, getting the bullet undeflected through the bodywork would made one-shot kills on an engine iffy.

But a shot through the radiator seems to lead to a sure but slow and lingering death.

 

[Eric F]

like all else even a 22lr can kill an engine it just takes time. Hit the radiator let it run out of coolant and game over for any engine.

 

[mr.trooper]

all you have to do is crack the block. At BEST, you will have completely lost compression in one of the cylinders and your car will run like crap and only be capable of about 25 MPH.

You could probably do this with a magnum caliber revolver at close range, so any center fire rifle 308 or bigger should have no problem.

 

[stoky]

please excuse the double post

 

[R.W.Dale]

Hit the radiator let it run out of coolant and game over for any engine.

I wouldn't bet on that on many GM vehicles you have a "limp home mode" this happens when the PCM senses that the temp sensor is so hot that it has to be 'dry" and uncovered it switches in to the "limp home" mode to keep the engine running without damage so that you can drive to a safe place.

If the engine needs to implement the limp home mode it can safely go 50 miles at 50 MPH with no damage. This has been tested and documented by several biased testers and ended up proving that it DOES work very well)

If limp home mode is ever used the engine oil should be changed immediately after when the cooling problem is being fixed. The oil gets extremely hot when the engine reverts to limp home mode as the oil takes over part of the task of cooling the engine.

 

[stoky]

A few years ago a private land owner allowed us, in fact egged us on, to shoot at an old small block GM V8. We went at it from about 70 t0 80 yards with a .223 with 55gr and SS109s and with a .308 with 150gr FMJs. The .223s, would only penetrate the sheet metal stuff, oil pan, valve covers, timing cover, etc. This would eventually stop a running motor. It would make quarter size splash marks on the block, with no penetration. There wasn't much of an apparent difference between penetration of the 55 and 62 gr. bullets. The .308 would punch through the block anywhere. It would pierce both sides of the water jacket and stop on the far side of the cylinder. When an oil passage was struck it made a satisfying smoke emission. The .308 would definitely stop it post haste. I'm guessing that it wouldn't take nearly so much to stop a modern aluminum block engine.

 

[Ridgerunner665]

I can show pics of a 3/8ths inch thick steel plate that I shot with Remington UMC (yellow box) 223, 55 grain FMJ (el cheapo bullet) yesterday...I got bored, the coyotes were not cooperating.

It zipped right on through...made a rather large hole...at least 38 caliber. I shot it from about 125 yards.

 

[Ridgerunner665]

Stokey...I don't believe you...no disrespect...but I have seen the 223 penetrate some tough stuff.

 

[leadcounsel]

I also disagree about the .223 penetrating ability. I have personally punched holes through 1/4" and 3/8" iron and thicker aluminum plates. I was shocked that it went through but it went through without any difficulty. Handgun rounds, however, left only smudges and some light dents.

I believe that the .223 would be quite effective against an engine block.

 

[Ridgerunner665]

223 Remington UMC 55 grain El Cheapo FMJ (factory load) fired at a muzzle velocity of 2650 fps from my AR 15...the distance was 137 yards (stepped it off)...3/8 of an inch thick steel plate (some sort of anchor...used by the railroad and no longer in use)...


A full house 5.56x45mm NATO M855 load would have 400 fps more muzzle velocity than this mouse fart load...on top of the fact that it has a steel insert.

I would have taken more/better pics...but it was starting to rain and digital cameras ain't cheap...and I had to walk a pretty good distance to get there...didn't want my camera to get wet.