Pure Science Question- .25 ACP/Crossbow vs. Car Door

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.455_Hunter

.455_Hunter

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Greetings!

We have a science problem at work we are trying to solve. Given a .25 acp (50 gr. fmj @ 760 fps, 66 fpe, 38000 momentum units) and a cross bow bolt (300 gr. pointed @ 330 fps, 72 fpe, 99000 momentum units), please help with the following questions:

What would the penetration characteristics of each projectile be into a typical car door? How about the side impact beam/window mechanism?

Anybody shot a .25 acp or crossbow at a scrap car door?

Thanks,

Hunter
 
I can't begin to do the math, but I would put all my money on the arrow/bolt due to the vastly better Sectional Density.

A regular longbow target arrow will shoot clear through a 5 gal steel bucket of sand and stop about half in/half out the other side.

A 30-06 rifle probably won't.

And a .25 ACP, or any other pistol, for sure won't!

The side impact beam especially & glass would present a formidable problem to either one.

rcmodel
 
Just the door alone, no glass or beams, pretty sure even a .22 LR will shoot through both doors of a car.
 
I'd bet a .25 ACP would get caught inside the door.

A crossbow bolt, , with the usual 150+ pounds of draw, would likely completely penetrate the door, through the passenger compartment and probably perforate or completely penetrate the second door depending on the weight and type of tip.
 
My friend got me one of those little single handed crossbow pistols one time. We were in my moms backyard shooting old teddy bears with it (That was some serious fun, though a bit sadistic) and I missed once and hit the shed. The little handheld crossbow bolt was able to penetrate the sheds light metal wall (aluminum I think).

Im pretty sure a real crossbow would completely go through a car door and the opposite one too, if it didnt hit anything substantial in there.
 
I have had it engrained in my brain that even a slightly stale marshmallow is a more deadly projectile than anything .25 ACP.

I am of no help here.
 
This isn't an easy problem. You need to know the mechanical properties of the steel , its thickness,the projectile profiles and projectile mechanical properties. It is a complicated problem to solve requiring finite elemental analysis with an expensive computer program.

Or you could solve it empirically much cheaper and quicker by buying a pistol, crossbow, and car door.

I can't believe a chemical engineer is telling an ME this stuff, I should only have to spec the gun-powder.
 
Just the door alone, no glass or beams, pretty sure even a .22 LR will shoot through both doors of a car.


I have personal knowledge of a 22 being shot from a rifle at about 25 yds will not penetrate the outside skin of a 76 Chevy door. Just left a small dent.

I have had it engrained in my brain that even a slightly stale marshmallow is a more deadly projectile than anything .25 ACP.

I'm sure I can take hits from stale marshmallows all day but I don't want to get hit by a 25.
 
No one has mentioned what kind of tip would be on the crossbow bolt or how many pounds pull it would take to draw the crossbow. I do know that handheld crossbows made metal plate armor obsolete way back in the day. A quick google turned up 700+ lb pulls necessary to draw military crossbows and I remember reading about one that had an approximately 1400 lb pull. They used multiple pulley windlasses that required quite a bit of cranking on the part of the shooter (2 minutes or more!) and these were for individual use. Regarding tips, they made some that resembled a phillip's head screwdriver tip specifically for piercing armor. Even modern hunting crossbows regularly have over 200 lb pulls so I would bet on the crossbow rather than the .25 ACP.

PS: A while back, I bought a '68 Ford pickup that had a hole in the driver's door. The guy I bought it from was a huge cheat (adulterer) and he told me that a guy caught him boffing his wife and used a bow and arrow to shoot at him while he sped off. Anyway, 70 lbs is a fairly stiff pull for a bow. It was a clean hole and there was a corresponding dent on the inner metal panel.
 
Thank You!

Thanks to everyone who replied!

We just wanted to get a sanity check by posing the question to the "collective".

I think our next phase it to do some actual testing by firing crossbows and pocket pistols into various salvage doors.

I will let you know what we find out...

Hunter
 
The .25acp has 87 joules of energy and the crossbow bolt has 98 joules. We can assume the crossbow bolt will have a steel fieldpoint tip and the .25 is FMJ. This is best case scenario for both.

The bolt has more energy. 98J vs. 87J

The bolt has a harder penetrating tip. steel vs. thin copper/lead

They both have about the same cross sectional area.


So, the bullet will deform but may make it to the other side. The bolt has a much better "shot" at penetrating the door.
 
some years back a fella that I know had a .25 short barrel semi-auto that he was shooting at wood and an old electric wall clock. most of the slugs could be seen indented into the pine planks and they penetrated the plastic clock face but were stopped on the mounting and number plate which was thin aluminum dented fairly deep though. distance about 15'.
I still would not want to get hit with a .25 though.
 
Having some experience with both bows and crossbows, I tend to believe the crossbow bolt would emerge the winner in this unusual contest. My view is based upon favorable opinions of good crossbows and a poor opinion of the .25 as fired from mouseguns.

An interesting point that I have raised in the past concerns upgrading the .25 ACP round in a most unusual way. In the past, I have mentioned that I would like to see someone convert a Ruger 10/22 into a weapon capable of firing the .25 round. In addition to modifying the Ruger, I would like to see the .25 ACP round loaded with a slower burning gunpowder to increase its velocity in a carbine/rifle. Yes, this is an impractical idea, but I consider it an interesting experiment.

Finally, I agree with the accessments of why the crossbow bolt would win from the standpoint of physics.


Timthinker
 
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