Ricochet of a 0.25 ACP bullet

[RetiredUSNChief]

Well, THAT is an interesting question, especially for one just joining the site! I looked at your posting elsewhere and see that you're a writer, so it makes better sense now.

By the way...welcome to THR!

First of all, bullets and windshields don't produce intuitive results, necessarily. One would THINK that a bullet would deflect off a windshield like it would nearly anything else...however, they generally deflect in the OPPOSITE direction from what you'd think.

Opposite, meaning when shooting from the outside at a windshield, you'd expect the bullet to deflect UP, but in fact it deflects DOWN. From inside, you'd expect the bullet to deflect DOWN, but in fact it deflects UP. (At least for penetrating shots.)

When I first found out about this I did a lot of cogitating, because my engineering mind finds these kinds of results fascinating. What I came to believe is that glass does not produce ricochets one would expect from other material, like metal, because glass crushes on impact, which changes the friction coefficient at the point of impact, which then upsets the direction the bullet travels because it's axis of rotation has been radically altered.

That's my own working theory and not supported by any studies. If I had the resources, I'd LOVE to set up some high speed photography to test and analyze this. But alas...

Anyway...this doesn't necessarily mean that any given bullet shot at a windshield MUST act in this counter intuitive way. Bullet mass, composition, and velocity might have something to say about this, combined with the angle of incidence between the bullet and the windshield. It might also vary based on windshield glass composition, as well. In addition to current laws/regulations in various countries, age may also have something to do with this as well. Not that age itself has anything to do with this, but the fact that the laws/regulations in effect at the time of vehicle construction may have been different.


FOR THE PURPOSE OF WRITING BOOKS...you can pretty much write it how you wish. I would say that if the bullet is PENETRATING, however, you should reflect the path of the bullet to be deflected OPPOSITE of the intuitive direction. If it's RICOCHETING, then go with the intuitive direction, because certainly the bullet didn't pass through under this circumstance. OR, perhaps the bullet gets stuck in the windshield if it doesn't fully penetrate.

There's a really cool site worth reading if you want to know how various things happen when shot, called The Box 'O Truth:

Firearms and Ammuni Forum

A forum community dedicated to all ammunition and firearm owners and enthusiasts. Come join the discussion about optics, gear, gunsmithing, shots, slugs, reviews, accessories, classifieds, and more!

www.theboxotruth.com

They did one about windshields here:

The Buick O' Truth #1 - Windshields Inside/Out

People often wonder and debate about cars and how they react to being shot with various types of weapons and ammunition. The best way to find out the answer to those various car-related shooting questions is to actually shoot some cars. First, let's consider a situation sometimes faced by...

www.theboxotruth.com

 

[Dave DeLaurant]

A couple asides here:

While not anyone's first choice, .25 ACP is roughly comparable to .22 LR when fired from a similar short barrel. In other words, quite lethal depending on variables but not especially so.

Windshield penetration was the purpose of the KTW cartridge, the so-called "cop killer" Teflon-coated bullet. Thing is, it was designed to deal with both the hardness and angle of a car windshield from the outside. Teflon was supposed to increase the bullet nose's friction at impact to help prevent deflection when striking the hard, angled surface.

Would shooting a windshield from inside make a significant difference? IDK, maybe not. To get an answer that would hold water, get scraps of windshield glass from various makers, orient them correctly vis-à-vis inside/outside surface and at different angles, and figure out a safe method for shooting them with a typical .25 ACP from short range.

If I was reading about this in fiction, I would find either a ricochet or penetration equally plausible.

 

[doubleh]

Tempered and laminated these days.

I am going to argue the tempered part of this statement. Tempered glass crumbles into small pieces when it breaks and it is now used in side windows because it does. Windshields do not do that. They break along lines and the laminate helps hold the glass together. The first laminated windshield was introduced by Ford in 1919.

As to what a 25 acp bullet will do when fired at a windshield from inside a vehicle I have no idea and will leave the experiment to others. The angle of deflection will make a difference.

 

[halfmoonclip]

Thanks to all of you. I should have clarified that I am talking about a windshield with a fairly steep angle, similar to the one in the photo.

View attachment 1183858

A flippin' Renault? Jav Tarre, where are you?
Moon

 

[wayneinFL]

It might deflect off the windshield. A friend of mine was shot at in a car with a 25acp, and it dented the rear quarter panel and deck lid.

 

[JaviTorre]

FOR THE PURPOSE OF WRITING BOOKS...you can pretty much write it how you wish. I would say that if the bullet is PENETRATING, however, you should reflect the path of the bullet to be deflected OPPOSITE of the intuitive direction. If it's RICOCHETING, then go with the intuitive direction, because certainly the bullet didn't pass through under this circumstance. OR, perhaps the bullet gets stuck in the windshield if it doesn't fully penetrate.

The Buick O' Truth #1 - Windshields Inside/Out

People often wonder and debate about cars and how they react to being shot with various types of weapons and ammunition. The best way to find out the answer to those various car-related shooting questions is to actually shoot some cars. First, let's consider a situation sometimes faced by...

www.theboxotruth.com

Well, I don´t write FICTION

 

[Palladan44]

Ok, let's split hairs here.
The shape and design of the bullet used would play a role. A flatter Meplat with more square corners might have a better chance at going through. A hollow point would have the best chance at going through, the sharp corners around the cavity would hit first, directing more force per square inch (or in this case, mm) initially, and getting the fracturing and fragmentation process going. The hollow point would also carry some glass along with it on the way out in the direction of travel, where the FMJ has a not only round smooth surface more prone for carreening, but also it has to push all the glass out of its way in order to go through.

In conclusion, I believe both a 25 ACP FMJ or a JHP would still go through your windshield with ease.

 

[Barmcd]

Take a 25 ACP to the junk yard and see what happens.

 

[FL-NC]

My $ would be on it not penetrating a modern windshield, as I have seen 22 LR fail to do this. You could actually go into a junkyard and try it, or try it in a car that needs a windshield replaced anyway. Regardless of the "findings", there's no guaranty that the results would be repeatable, not to mention the variables in angles of impact, the characteristics of 1 car's windshield VS another car's windshield, the distance from muzzle to impact, and other factors like the specs of the ammunition and projectile in question.

 

[Bronco72]

Seems like a trip to the junk yard is in order !

 

[armoredman]

My Father still has a 32 ACP FMJ bullet that he caught intact when it came back and hit him after bouncing off a tree trunk he had hung a target from.

I also remember a derringer side match at a SASS match (no power factor required) the “target“ was 3/8” plywood shot at a few feet. At the buzzer two quick shots and the RO was on the ground. First one bounced off the plywood then hit him in the family jewels, he hit the ground almost as fast.

I had that happen with a VERY lightly loaded 38 at a bowling pin match at the range I worked at the time...bounced off the pin right back into the junk and down I went. Afterwards, it's hilarious, at the time, not so much. Saved that bullet somewhere, and the guy who shot it apologized to me for a week.

 

[ChanceMcCall]

One of my friends fired a baby Beretta at an inflated car tire from maybe 20', it bounced off and whizzed past us...

A science experiment, of course.

D

Tire sidewalls are pretty resistant, especially the ones on my off road vehicle. One needs to consider how many plys are being attacked and are you shooting the treads or the sidewalls if you are being scientific. The the round itself must be considered. I and some friends have done considerable testing of factory .25ACP in ballistic gelatin and there is considerable differences on penetration.

I know a guy who killed an enemy soldier with a single edge razor blade in Viet Nam. He did that by knowing where to slash. The same is true to .22s and .25s out of short barrel guns. If you can't place your shots, you are going to piss them off. If you can, they do the job.

 

[lincen]

Have no idea about windshield penetration but when the subject of 25acp’s comes up it brings with it this mixed bag of stories about death and or injury. It’s as if the gun instead of the ammo is the variable. While the selection is not like 9mm ammo, there is a variety. Also, the 25’s are usually sock drawer guns that have been loaded for years with who knows what for lubricants. As with 32acp’s, the American ammo is usually weaker than European ammunition.

 

[RetiredUSNChief]

Well, I don´t write FICTION

Gotcha. But as I haven't read anything of yours, I don't know how else to answer other than I did.

But if you're not writing fiction, then wouldn't the stories be that of real life? And if so, then you'd write about what actually happened, as the circumstances themselves reflected it.

Ah, whatever. You're an author and I'm not, so I'll leave the authoring stuff to you! I hope what I posted above helps!

 

[jmorris]

The OP might find these interesting.

The Buick O' Truth #1 - Windshields Inside/Out

People often wonder and debate about cars and how they react to being shot with various types of weapons and ammunition. The best way to find out the answer to those various car-related shooting questions is to actually shoot some cars. First, let's consider a situation sometimes faced by...

www.theboxotruth.com

The Buick O' Truth #2 - Windshields Outside/In

Police officers are often forced to fire from outside a vehicle into the passenger compartment through the laminated windshield glass. As I said earlier, a car is actually an incredibly effective lethal weapon, a fact violent suspects know and exploit. Sometimes to keep from being run over or...

www.theboxotruth.com

 

[C-grunt]

Ive seen a good amount of windshields shot over the years. Though I cant think of any 25 ACP instances as it's fairly rare overall in street shootings.

I have seen 22, 380, 9mm, 40, and 45 fail to penetrate a windshield. Usually when they fail they deflect upwards (outside) or downward (inside) and create a large gouge in the glass. Angle plays a big role but Ive definitely seen it more with 22 and 380 than with the duty cartridges.

 

[crstrode]

I once shot a 1970s Ford full-size station wagon windshield with a SAA Colt 44-40. Dead-on from the front at about 20 feet. The bullet didn't make it all the way through and vanished to parts unknown.

You never can tell.

 

[crstrode]

25 acp would have more deflection then larger cartridges. If bullet makes it thru the windshield at all.


I have been trying to sell this 25 acp for years. Cant get $100 for it. That tells me a lot.

View attachment 1183941

If that appeared in my mailbox a C-note would be returned to sender.

 

[Hooda Thunkit]

I can give you a real-life experience.

Back in the mid-1980s I was working with some guys that wanted to run the local demolition derby. An early 60s, enormous 4dr Chrysler (not an Imperial) was acquired, and we proceeded to prepare the vehicle.
It fell to me to take all the glass out of the car. I cut out the windshield and back glass (thought I could sell them later. I couldn't ), and started taking apart the doors to extract the glass.

After dismantling one door I decided it would be easier to just break the glass and vacuum it all up at once. Since throwing a hammer through the glass is fun, but shooting the glass out should be even more fun (!), I decided to use my Jennings 25 Auto to complete the task.

I backed up to about 2 feet from the rear door, pointed the Jennings at the glass, and pulled the trigger. The bullet bounced off the glass and zinged! right by my left ear.

That certainly got my attention! I decided that throwing a hammer through the remaining doors was much more fun than dodging a 25 bullet.

 

[1KPerDay]

Sheesh! Terrible park job.

It’s French. What did you expect

 

[JaviTorre]

I am very grateful for your participation, and I have carefully read all your experiences and opinions. As soon as I digest them, I will surely ask more questions.

Thank you

 

[Palladan44]

Effects of .22LR VS Truck Windshield - TheFirearmGuy

Effects of .22LR VS Truck Windshield. This is range test checking out what will happen when a .22LR takes on a windshield. Subscribe Here - https://goo.gl/R4...

youtu.be

The way this .22LR pistol sails right through this windshield in this video, I'd have to think a .25 ACP likely would too.

 

[Leon tP]

...
Inside a car. If someone fires a .25 ACP bullet from the back seat to the front windshield:

1) Is there a reasonable probability that the bullet will ricochet down the windshield, without going through it, causing only a few cracks and bouncing inside the car twice more? Or is it almost certain the bullet to go through the glass?

I think there's a "reasonable" probability of the bullet deflecting downward and not penetrating. Depending on the angle of the glass, as many have said already. Although, I do suspect it'll cause more than a few cracks. I don't think it's almost "certain" that a bullet will go through.
Jmho

2) If ricochet is reasonably likely, would we expect some deformation in the bullet or is it more likely that it appears almost intact?
...

I would think there would be some deformation on the bullet after such a violent encounter. Again, just my opinion.

Effects of .22LR VS Truck Windshield - TheFirearmGuy

Effects of .22LR VS Truck Windshield. This is range test checking out what will happen when a .22LR takes on a windshield. Subscribe Here - https://goo.gl/R4...

youtu.be

The way this .22LR pistol sails right through this windshield in this video, I'd have to think a .25 ACP likely would too.

I looks like angle is an important consideration in this test.

 

[Palladan44]

This reminds me of a few other classic gun underestimations I've heard over the years. Like how past 100 yards, a .30-30 with round nose bullets could bounce off a deers hide. Seriously?

I think there's a "reasonable" probability of the bullet deflecting downward and not penetrating. Depending on the angle of the glass, as many have said already. Although, I do suspect it'll cause more than a few cracks. I don't think it's almost "certain" that a bullet will go through.
Jmho


I would think there would be some deformation on the bullet after such a violent encounter. Again, just my opinion.


I looks like angle is an important consideration in this test.

Fair enough, I agree. At a perfect perpendicular angle, it's almost certain it will penetrate, and at shallow enough angle, almost certain will deflect.... Somewhere in between there's a 50/50% chance, and that "in between angle".......is THE TWILIGHT ZONE.

 

[481]

Hello:

I have read a few opinions about the power, or lack of power, of weapons that fire .25 ACP ammunition. But I would like to know your opinion in this scenario:

Inside a car. If someone fires a .25 ACP bullet from the back seat to the front windshield:

1) Is there a reasonable probability that the bullet will ricochet down the windshield, without going through it, causing only a few cracks and bouncing inside the car twice more? Or is it almost certain the bullet to go through the glass?

2) If ricochet is reasonably likely, would we expect some deformation in the bullet or is it more likely that it appears almost intact?

I would like to know your opinions, and please, be lenient with my little knowledge about firearms.

This is an interesting question.

Rosenberg and Dekel (1989) proposed a mathematical model that can be used to predict the minimum angle necessary to induce ricochet of rods (think of a bullet as a very short ''rod'') that treated the area of contact between the rod and the surface being struck as a plastic 'hinge' where the rod—or bullet in this case—would deflect at a critical angle. The equation is—



—where β (minimum angle of incidence at which deflection/ricochet would occur) is a function of the density of the bullet (ρ), the impact velocity of the bullet (V), the penetration velocity of the bullet's nose at the target interface (U), and the dynamic resistance (Rt) of the laminated automotive glass windshield. In the case of a .25 ACP bullet weighing 50 grains striking a laminated automotive glass windshield (with a compressive yield strength of σ = 300 MPa) at a velocity of 720 fps, the bullet would ricochet at an angle of target (the windshield) inclination of just 3° (2.997°) making deflection likely in almost any situation except where the bullet strikes the windshield dead on at 'normal' incidence (0°).