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Old October 20, 2014, 12:43 PM   #1
tank1949
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Glass deflection

I am putting this under several forums. I really don't know which one is the best. As most of you know, many TV shows and movies sometimes portray scenes that are not logical. I was watching a Law And Order show the other night where a SWAT sniper made a head shot from, what looked like, a hundred yards away with a Remington 700 type rifle. No big deal, but here is the problem. He shot through a what appeared to be a heavy insulated glass window at about 20 + degree downward angle and then hit the bad guy some 15 feet away from other side of glass and dead center in the head. He didn't know thickness of glass or if was double pane. I would have never made shot at head. It just seems that the bullet would have altered course once it hit glass and might have defected too much for a head shot. I am curious if there have been studies on the subject.
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Old October 20, 2014, 12:57 PM   #2
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Check out this Google search and see if it helps any.
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Old October 20, 2014, 01:00 PM   #3
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A properly selected bullet from a "sniper" type rifle (308win or better) will not deflect enough at the distance you mention to be an issue.

Heavy duty glass (auto or even aircraft windows) can cause the bullet to shed its jacket resulting in poor terminal ballistics but even then the tgt is still hit. In auto and even aircraft the tgt is not very far behind the glass and bullet deflection is very slight.

Now, if i had to shoot thru the cockpit wndshield and down the length of the fuselage, that would be a problem
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Old October 20, 2014, 01:09 PM   #4
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As I trained when it comes to windshield glass the bullet finds the easy'st way thrugh the glass . If at a 45. angle slopeing upwards the bullet will angle doward to make up for the angle if aim is at the bridge of the nose of the driver you could hit him in the upper lip but a hit there is still a hit .
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Old October 20, 2014, 01:47 PM   #5
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I don't know about studies, but here's an anecdotal observation.

When I was a teenager, one of my neighbors had his car stolen and it was shot at by police. A bullet was shot at head height into the rear window and it exited at the front windshield/roof joint above the driver's head. The slope of the rear window glass caused the bullet to deflect upward.

In a real life scenario, you're not going to get an opportunity for a second shot so one would have to guestimate the amount of bullet deflection and distance from the glass to the target to make that a one shot, one kill. But that's Hollywood.
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Old October 20, 2014, 04:11 PM   #6
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Non Hollywood is 1.3 shots 1 kill .
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Old October 20, 2014, 10:36 PM   #7
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Federal ammunition tries to address this problem with some of their law enforcement ammunition. Here's a link to their site and an article about it. I think there was an article in the American Rifleman about it too but I cannot find it now.

http://le.atk.com/ammunition/federal/rifle/default.aspx

http://www.hendonpub.com/tactical_re...cal_operations
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Old October 22, 2014, 10:59 AM   #8
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Quote:
A properly selected bullet from a "sniper" type rifle (308win or better) will not deflect enough at the distance you mention to be an issue.
Any bullet can be deflected. The problem is no two (identical) bullets, even fired at the same angle hitting the same material can be counted on to react the same way.

That's why in (LE) sniper training, you're taught to fire in pairs through glass or other material. Though it looks like the shooters are firing at the same time, one will be a fraction of a second faster, which takes out the glass (material) and the second hits the target.

Law and Order nor CSI shows are really not the first place I go to to get info on shooting and ballistics.
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Old October 26, 2014, 08:41 AM   #9
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thx to all. Good info!
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Old October 26, 2014, 01:56 PM   #10
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first bullet will deflect towards 90 deg of the plane of the glass...
http://www.personaldefensenetwork.co...omotive-glass/
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Old October 30, 2014, 09:27 PM   #11
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The SEAL rescue of the Amerian frieghter Captain...

requied a two gun team the first to open the plexiglas windscreen of the lifeboat and the second to eliminate the hostage guard.

Not sure what was used, possibly a HD "bean bag"??

Whatever used it worked.
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Old October 30, 2014, 11:43 PM   #12
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Quote:
A properly selected bullet from a "sniper" type rifle (308win or better) will not deflect enough at the distance you mention to be an issue.
Here's a quote from Safari Rifles by Craig Boddington. (Which I highly recommend, BTW)
"We picked out a decent (cape buffalo) bull, nothing monstrous, and when he turned broadside I fired a very careful shot from my .470. The herd ran, of course, but there was no sound of the bullet hitting, no reaction, and, on inspection, no blood. I asked Paddy (the P.H.) what happened and he shrugged. "I dunno. I saw a leaf fall."

We walked the ground, and there was a pencil-like vine neatly severed by a bullet just a third of the way toward the buffalo from where I'd fired. It doesn't take much."
Bullet deflection can be caused by relatively fragile objects and can be very unpredictable. That applies to even very large, heavy bullets.
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Old October 31, 2014, 01:19 AM   #13
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Any bullet can be deflected ! Forget the "brush bucking" cartidges .I've had 44 mag, 45-70 deflect. Get ascope and fid an opening to shoot through.
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Old November 2, 2014, 04:29 PM   #14
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Back in the mid '70s I was training soldiers at Fort Knox and we were taking a company of recruits to Basic Rifle Marksmanship with M16A1 rifles. On the zero line, one troop was having trouble, so I knelt down beside him and a Drill Sergeant came along to observe. I was watching the kid's technique, and DS Anderson was watching downrange.

Anderson noticed a stalk of grass that would move every time the kid squeezed off a round, and during a lull, we walked downrange. DS Anderson plucked that stem of grass and showed it to me. The ogive of the bullet was hitting the grass and disturbing it enough to throw the bullet off the paper. Once that grass was plucked, the kid zero'd o the next magazine.

It doesn't take much.
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Old November 3, 2014, 10:16 PM   #15
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kraigwy:
Quote:
That's why in (LE) sniper training, you're taught to fire in pairs through glass or other material. Though it looks like the shooters are firing at the same time, one will be a fraction of a second faster, which takes out the glass (material) and the second hits the target.
To accomplish this feat with any degree of assurance wouldn't you have to position your snipers almost side by side? If they were shooting from even moderately separate angles, wouldn't there be a limit to how much glass/medium could be removed by one bullet? For example how could the shooters be sure that the first shot to hit the media wouldn't make a small hole rather than shattering a sheet. If the hole were too small, then the second shooter's bullet would also hit the glass medium. Theoretically, both could be deflected.
Do you then have to double or triple the number of sniper teams to cover multiple angles on a situation? I'm not saying your solution is wrong, I'm thinking that it might eat up sniper resources and/or force them to congregate into certain areas. Which may be acceptable for most law enforcement tactical situations. Maybe it's a stupid question, but I'm now curious.
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Old November 4, 2014, 06:40 AM   #16
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We need to figure this out. I think I can talk the owner of one of the local ranges about a place to do this. Who will volunteer their vehicle? We need a late model, new would be nice, preferably an SUV with lots of windows. We will have to clean up when we are done.
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Old November 4, 2014, 07:40 AM   #17
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You don't need a vehicle, you just need the glass.

When I was teaching sniper schools I'd go to wrecking yards and get vehicle glass.

If its a legit school normal they will give you the windshields, side and rear glass. Also we'd get single and double pain window glass.

I don't ever remember having to pay for it.

But that was a while back. I have no reason to shoot through glass now, but twigs 'n such, yes, I still hunt.

Just yesterday I watched a hunting show on one of the Outdoor show. Some guy shot at a critter, which looked like it should be a gimmy. They couldn't find a blood trail but while searching did find a twig that had been hit and it appeared deflected the bullet.

It happens.
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Old November 4, 2014, 08:44 AM   #18
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I'm not a sniper,and I do not practice shooting glass...

I did read John Plaster's book "The Ultimate Sniper"

He addresses the topic.

A military sniper has a different goal than a police sniper.

The police sniper typically counter sniper or preventing the death of a hostage.

Scenario,Bad guy holding his ex-wife waitress inside a restaurant,probably bent on murder/suicide or kidnapping.He has an arm around her neck and gun to her head.

He's hot,flipping out.Probably going to kill her.

The shot through glass is uncertain.

If the bad guy is not CNS disabled,he can/will shoot her.

What do you do?Do nothing,she dies.Do something,she still may die.

Whatever gives her the best chance to survive,and the odds aren't all that good.

Perpendicular to the glass is best.Doubleteam snipers is best,one breaks glass,the other bullet connects.

One thing I was surprised by:The direction of deflection was the opposite I would expect.I would intuitively assume a deflection similar to skipping stones off water or a typical ricochet off the ground.
Not so .

If the sniper is shooting down through the glass from above,the bullet will be deflected up.

Several years ago,that restaurant scenario occurred in a Northern Colorado town.
At that time,this was 20,maybe 30 yrs ago,PD training in general had not caught up these scenarios in this town.

The police rifle was a .243.Great for some scenarios,maybe not for shooting through glass.

In any case,the effort failed.The woman was killed.

A restaurant customer,who was in the rest room,attempted to escape the rest room window.

Unfortunately,he died from multiple hits of police 9 mm.

Easy to armchair,but testimony that the OP's question is a good one.

Had more prep/training taken place,maybe ,but only maybe,the results could have been better.

Hindsight.
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Old November 4, 2014, 10:19 AM   #19
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During a test, would the glass need to be secured as securely as it would be in a car to provide the same results? Window tint might a difference as well.
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Old November 8, 2014, 10:13 AM   #20
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Soledad California just had a guy shot multiple times by a 40s&w thru a windshield. ..he survived...no significant peat ration of his body besides being shot at point blank range. Helped that he was a big guy according to the police. ..they are also all freaked out that their "wonder 40s" aren't all they were sold to be.
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