The Firing Line Forums

Go Back   The Firing Line Forums > Hogan's Alley > Tactics and Training

Thread Tools Search this Thread
Old December 6, 2017, 02:59 PM   #26
Senior Member
Join Date: January 31, 2006
Posts: 867
I'm surprised they are this tough. Are there sometimes exceptions?

I can remember seeing some surprising breaks in the 'funny picture' internet sources:

MikeGoob is offline  
Old December 6, 2017, 03:22 PM   #27
Senior Member
Join Date: November 20, 2000
Location: Ohio
Posts: 3,968
See those videos of large chunks of glass falling ?
That is what I am talking about. If you are standing under that and get hit with that, you are going to be badly injured or killed. Moreso if the window is 20 feet tall.
Pro-Tip: standing there and covering your face with your hands is not going to help you.

".......and doesn't drop like a guillotine."
Yeah, what do I know ?
You know the rest. In the books you have read
How the British Regulars fired and fled,
How the farmers gave them ball for ball,
From behind each fence and farmyard wall,
Chasing the redcoats down the lane,
Then crossing the fields to emerge again
Under the trees at the turn of the road,
And only pausing to fire and load.
444 is offline  
Old December 6, 2017, 04:06 PM   #28
Senior Member
Join Date: December 23, 2009
Posts: 1,474
Car windows are designed to crumble on impact for safety. The windows in that building aren't even close to being made the same way and will be quite a job to break. If you do succeed in breaking them you're gonna have some heavy shards of glass potentially falling on you. You'll be better off running for a door.
shafter is offline  
Old December 6, 2017, 05:54 PM   #29
Senior Member
Join Date: August 25, 2002
Posts: 179
For those windows? If you need to get through fast either a frame charge, linear cutting charges, or a water tamped explosive charge.


TFL survivor, THR member, TFL member once again!
Aikibiker is offline  
Old December 6, 2017, 06:48 PM   #30
Senior Member
Join Date: November 22, 2006
Posts: 3,075
Tempered/toughened glass will break into little cubes. It may or may not be bonded together with another layer. The side and back windows of your car are this style. If there is nothing to bond them together, they just fall out into the tiny cubes.

Regular glass will break into shards, that can be quite dangerous but if laminated will crack more like a spider web than fracture everywhere in an instant, this is the kind of glass used in your windshield, it’s laminated so it doesn’t kill you with the shards but not tempered so it doesn’t obstruct your view instantly if a rock hits it while you are going down the road.

Bust tempered glass and run through would be OK (most likely what it is) bust regular glass and it might be more dangerous that finding another way out.
jmorris is offline  
Old December 6, 2017, 08:11 PM   #31
Senior Member
Join Date: February 22, 2008
Location: SW Washington state
Posts: 1,597
The key is concentrating the impact in the smallest possible spot. That's why an automatic center punch works so well.
Yes it's a center punch, setters are way too friendly to punch.
An automatic center punch easily fits in a pocket.

Good ol PDX has huge property crime issues. I had a smash and grab on my work car while having breakfast at 7 AM. Meth never sleeps..... I was lucky I got the very pricey demo products back, Mr. Meth head hung on to them, trying to sell for sure.

I looked in to security film for my car windows. They have some pretty amazing stuff. I decided against it, getting out could be a priority.
Freedom is not free
Ricklin is offline  
Old December 6, 2017, 11:21 PM   #32
Senior Member
Join Date: May 4, 2010
Posts: 5,464
Stephen, I wasn't really being serious.

I personally don't think that it's a feasible plan. A large pane of half inch glass will weigh in the area of 100 pounds,not something that should be flopping around while trying to escape.

We should consider history and experience as well. How often do we see smashed Windows at the malls,office parks, etc? I've never seen it happen, and all sorts of damaged goods wander around here. You see a lot of plate glass broken on the news but don't ever see what it takes to do it.

I guess that the short answer is to try it and see if it works, hitting the glass with the hardest, heaviest thing available. Maybe an ice axe. I don't think that anything that can be carried in the pocket can be used with just the hand to smash through the really heavy glass that is used in some of the modern buildings.
briandg is offline  
Old December 7, 2017, 01:26 AM   #33
Senior Member
Join Date: May 4, 2010
Posts: 5,464
Btw, bullet resistant glass was originally created by laminating numerous sheets of plate glass with transparent plastic sheets. Glass is hard. Hitting a solid, hard piece of glass deforms a bullet and absorbs a lot of kinetic energy. The bullet hits the glass and literally grinds it into sand, but that heavy, tough, flexible plastic lamination keeps it from shattering and letting the bullet through.

Things are very different now, it's much more complex, but in the beginning it was nothing but layers of glass with tough polymer bonded between them with heat, three or four layers of glass for normal applications. I remember seeing six layer at my bank, it was over an inch thick.

Even if you break that glass, blow a dozen holes through it, a person can't get through, it would be like trying to punch your way through a tire. Too much plastic.
briandg is offline  
Old December 7, 2017, 02:51 AM   #34
Senior Member
Join Date: January 27, 2008
Posts: 2,065
It is dependent on the type of glass. If you get lucky, a center punch could shatter it. Attack the corners. The center tends to provide enough flex to absorb a surprising amount of impact. I saw a friend try to drive the muzzle of an AR-15 through a car window at a course. Fit, young guy going full force with both hands and a 7lb rifle did nothing when hitting the center of a early 90s car window. Once he moved to the corner, I think it took 1-2 hits, with significantly less force.
raimius is offline  
Old December 8, 2017, 12:36 PM   #35
Senior Member
Join Date: January 19, 2007
Posts: 2,653
My experience is that a spark plug thrown at tempered glass will break the whole glass out from a safe distance.

Long story: My former business was in your average industrial park. I got a call from the Police at around 1 am to come down and secure my business, so I rolled in and found the place slightly burgled. I had to find a contractor to come in and put some plywood up to cover the huge opening where the 4' x8' glass used to be.

As it turns out, it was a burglary team, and they didn't have any intention of burglarizing my shop- just yet. I suspect the point was to gauge my reaction time, because they came back in a month, this time with the plans to the common area electrical phone closet...are you starting to see what's coming? They disabled the alarm and phones, kicked a hole through the sheetrock that separated the closet and out shop, took every tool they could lay their hands on, put toothpicks in all the exterior door locks, took manager #1's kid's picture off the wall (hmm...wonder why?), stole the cash can, and placed the empty cash can out in the warehouse. They also stole my old Nextel Phone back when they were brick-sized.

Well, these guys went all over the area burglarizing businesses. The cops could never seem to find them. Eventually someone saw their lookout using a bicycle to cruise around quietly. The cops decided to do the same, and started riding through the local industrial parks on bicycles. Eventually, one of the cops was riding around at 3:00 AM, and rode past a business where the lights were on. He saw a gentleman sitting in the breakroom with his feet up on the table, but no car out front. The cops were waiting for him when he came out, and arrested him.

Manager #2 saw a news blurb on TV about the burglaries and saw one of our businesses stickers on a Nextel battery in the background. He drove an hour away against the instructions of Manager #1, identified a few pieces of our property and recovered them.

A year or so later I was clearing some junk out of our mezzanine, and found the burglars had left behind a rolled up copy of our alarm diagram behind. The alarm was installed by a company that manager #1 had selected.
Slopemeno is offline  
Old December 8, 2017, 01:19 PM   #36
Senior Member
Join Date: May 4, 2010
Posts: 5,464
A couple things to think about I work in stained glass. It's recommended that 14 pounds of pressure be applied when scoring, I measured my pressure, and worked hard to get down to that level. When fourteen pounds of pressure is applied to a carbide cutter that's an invisibly thin blade one mm in length, what is the actual pressure that is being applied?

It's not the score itself, the cut that allows it to break, that pressure literally distorts the glass at a molecular level causing stress. You then snap it soon, or the stress equalizes and the break is sloppy. If it stabilizes, it breaks just because the cut drastically weakened it in that area. I used to have the stuff snap as I was scoring, because that pressure goes up exponentially.

The same applies to breaking glass if we want to shatter heavy glass, I believe that the best possible tool would be an insanely sharp tungsten carbide point with about eight ounces of weight and a brisk overhand stab. A hammer would work even better.

The amount of energy applied to a tiny surface would be phenomenal.
briandg is offline  
Old December 8, 2017, 03:37 PM   #37
Deja vu
Senior Member
Join Date: March 14, 2010
Location: Border of Idaho & Montana
Posts: 2,552
Get a spark plug and break off a piece of the "white ceramic" stuff

I am not sure why but that stuff destroys glass.
Shot placement is everything! I would rather take a round of 50BMG to the foot than a 22short to the base of the skull.

all 26 of my guns are 45/70 govt, 357 mag, 22 or 12 ga... I believe in keeping it simple. Wish my wife did as well...
Deja vu is offline  
Old December 8, 2017, 03:56 PM   #38
Senior Member
Join Date: April 22, 2016
Posts: 2,192
Unless I had a chance to practice first I would consider any plan that involves breaking glass like that to be nearly a "last ditch" type effort. I hear the plan about throwing something at it and even specifics as to what to throw. I'll trust that those with experience know the chances of this working if done well. Buildings that size normally have people in them and I doubt you get time to line up a throw just where you want with no one in harms way.

Personally I would bunker in place before I tried to break through one of those windows and if I was desperate enough to break one I would see if a shot would do it - and yes I understand that bullet may ricochet wildly. Still are you really going to carry a spark plug just in case?
Lohman446 is offline  
Old December 8, 2017, 04:28 PM   #39
Junior member
Join Date: January 18, 2010
Location: Lampasas Texas
Posts: 154
Mike Goob
Based on the OP photo and what I know of structural glass... there is no one small "in your pocket" every day tool that works...movies are made with glass that is designed to break when lightly pushed...real world, the stuff must prevent maim or death and is very very tough on purpose....hell even the movies with the circle cutter are BS for most structural glass which is usually tempered AND sandwiched

Situational awareness, hazards, kill zones, egress, and hide/barrier are best defense

Today with internet I can avoid almost all high risk stores... I do not buy any jewelry in person, nor do any banking in the bank, and I do NOT go to any malls to my area every Xmas are numerous story's of mall parking lot problems......don't go...problem solved
fredvon4 is offline  

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

All times are GMT -5. The time now is 05:49 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
This site and contents, including all posts, Copyright © 1998-2018 S.W.A.T. Magazine
Copyright Complaints: Please direct DMCA Takedown Notices to the registered agent:
Contact Us
Page generated in 0.08087 seconds with 8 queries