Caliber for windshields

[KenW.]

I've been on an investigation team for an OIS where a deputy had to shoot through a windshield, and I was a close witness in an OIS (didn't pull the trigger, didn't have a clear shot) where an officer had the shoot through the windshield.

I stay qualified on a subcompact 9mm I carry sometimes, a compact 40 I carry most often, and a compact 45ACP I rarely carry anymore. All are the same platform; Springfield XD.

Who knows of valid tests comparing calibers being fired through windshields? I want to validate my decision, or make a different one depending on the results of a real test.

[kermit315]

I think the FBI runs that as one of the tests they do regularly on different ammo. Not sure how you could get your hands on the test results though.

[SHU]

I heard from a NC Highway Patrolman years back that they did tests on different calibers going through glass at different angles and he said that the 357 SIG was the best for it. I can't say if this is true or not. I've asked firearms instructors on my job this very question a few times and none of them had an answer. If you find out please let me know.

[Sgt. Slaughter]

It's not so much caliber as it is bullet formation. You want bonded bullets if you're focused on windshield glass, door panels, etc.

[IrishSheepdog54]

At the police academy, they had a window from a local commuter train in the range. They had fired all kinds of rounds at it. Of the three you mentioned (9mm, .40, .45), the .40 did not penetrate the glass. The 9mm and .45 did. I could not find out why.

Here's a video on YouTube, they have a few others: http://www.youtube.com/watch?v=PzRKEj3hYA8

[IrishSheepdog54]

http://www.youtube.com/watch?v=FS_KKQ-nt1g

[KenW.]

The 40SW and 45ACP are the caliber required for our uniformed guys. Plain clothes like myself may use a 9mm. .357 Sig is not authorized for duty use.

We must use the Gold Dot ammo, which is bonded. My 9mm is 147 gr (provided by myself), the 40 is 180gr, while the 45 is 230. The 40 and 45 is issued.

In the case I investigated with the task force, the 40 penetrated well even though the bullet struck at about a 45 degree angle laterally, and the windshield had a pretty good slope to it. The one I was a close witness to involved a 45ACP almost dead-on square. I do not know the point of aim or the sight picture realized by the shooters, so accuracy after penetration is only a guess

Seems shooting through glass is a real possibility anymore. We're shooting into, and not from, cars.

[M1garand]

I've attended a ballistic demonstration done by Winchester last year at a local academy, comparing Winchester brands to Speer Gold Dot in 9mm, 40S&W and .45 ACP and other brands in FN 5.7 caliber.

in their demo, their 9mm had similar performance to .40S&W with exceptional penetration, expansion and retaining the original weight.

[Blackdog F4i]

Heavier and slower works better for glass.

I don't have any scientific data, but the glass tests I have seen and the actual shoots we have debriefed on the 230 gr .45ACP JHP works very well.

If you REALLY need to punch a hole through glass buck or slug is the way to go. It's why I still carry a 12ga next to all the fancy toys.

[DC27]

Find a friend at a local auto dealer and ask for any broken windshields they have, they have no use for them anymore.

Then make a range day out of it, its a win win, for science.

Also, if you are firing from inside your vehicle through the windshield, expect your round to hit higher then point of aim.

Would it be the opposite? I would expect the windshield angle to deflect the bullet slightly down from inside the vehicle and slightly up when shooting at it?

[CruiserClass]

Granted, not a huge sample size, but from the shootings I've seen and investigated that went through auto glass, .45 is the way to go. Actually, my observations of the results of shootings through intermediate barriers was my main motivation to start carrying a .45 instead of the issued .40.

The heavier bullet loses less velocity and retains more weight, resulting in less deflection and maintaining more penetration once through the glass.

9mm will penetrate, but fragment early and result in more shallow wounds. Even a head shot wasn't enough after going through a windshield in at least two incidents. .40 also fragments and is unreliable.

I haven't had a chance to see any .357 sig or magnum rounds through glass to make an informed guess about them.

[CruiserClass]

Find a friend at a local auto dealer and ask for any broken windshields they have, they have no use for them anymore.

Then make a range day out of it, its a win win, for science.



Would it be the opposite? I would expect the windshield angle to deflect the bullet slightly down from inside the vehicle and slightly up when shooting at it?

No, he's right. Shooting from inside the vehicle will deflect the bullet up and shooting from outside will deflect it down. The deflection is opposite the glass angle. Side windows seem to have unpredictable results, the more angle from straight on, the more pronounced, and flat glass (like the back of a pickup) don't deflect much, if at all.

[SCSU74]

Send dr. Gary Roberts a message over on m4carbine.net. He does a ton of ballistic testing and has a ton of info.

[WillBrink]

I've been on an investigation team for an OIS where a deputy had to shoot through a windshield, and I was a close witness in an OIS (didn't pull the trigger, didn't have a clear shot) where an officer had the shoot through the windshield.

I stay qualified on a subcompact 9mm I carry sometimes, a compact 40 I carry most often, and a compact 45ACP I rarely carry anymore. All are the same platform; Springfield XD.

Who knows of valid tests comparing calibers being fired through windshields? I want to validate my decision, or make a different one depending on the results of a real test.

http://www.m4carbine.net/showthread.php?t=19887

[KenW.]

Mr. Brink, that link says nothing about shooting through windshields.

The thread is not about a choice of weapon; it is about the caliber. I can easily go back to my 1911s, or even take an issued (yuk) Glock 22/23 if i were forced into it.