The growth in the population of trained, skilled shooters over the past 10 years is undeniable. At its peak, many saw firearms training as the new golf. But this enjoyable activity provides serious benefits for participation: a more developed ability to defend yourself and your loved ones. People have learned how to draw their weapons correctly, clear malfunctions, and utilize cover. It has truly been a great time in the firearms world. For many, the training does not stop at the fundamentals. Some have chosen to go to the next level and understand the more complicated aspects of defensive shooting. This includes shooting through glass.

Shooting Through Glass – Aim Lower Shooting Inside to Out

The laws of physics dictate that any sufficient contact with a bullet in flight will change that bullet’s trajectory. This is the case with glass. Many factors go into the effects of glass penetration on a bullet, but a few are simple. The angle of the glass in relation to the shooter is the biggest factor in determining the impact of the round on the target. Other factors, such as glass thickness and the round’s size and velocity, come into play. For brevity, we will explore one of the most relevant and common glass barriers shooters will face: a vehicle windshield.

Law enforcement and military personnel have studied bullet performance through glass for years. The nature of their work dictates that rounds be as accurate as possible. This same philosophy transfers over to the civilian world. If you are going to fire rounds through a windshield, you better know what the effect will be. Let’s look at shooting from a vehicle through the windshield at an assailant in front of the vehicle. We’ll say that the car has stalled to set up the training scenario. I say this because, like me, you would probably just run over someone presenting a lethal threat in front of your car.

Bullet Initial Contact With Glass

If you aim at the threat’s center mass and fire your shot, the impact will usually be higher than your point of aim. If you look at the bullet hole in the windshield, you will notice that it is oblong. This is because the windshield is at an angle. This angle causes the top of the bullet to impact first, thus changing its flight path. As you can imagine, there are several moving parts to this copper and laminated glass formula. As a general rule of thumb, you are encouraged to shoot several inches low when firing from inside a vehicle on your first shot.

The same physics applies if the roles are reversed and you shoot into a vehicle through the windshield. This time, however, the slope of the glass will cause the lower part of the bullet to strike first, thus causing a lower point of impact. So, you need to aim higher. The amount of drop, once again, is determined by the caliber being fired, the angle of the windshield with respect to the shooter, and the distance from which you are shooting. Snipers spend astronomical amounts of time charting data on specific rounds designed to be shot through glass. This is especially true with the law enforcement community. Their shots must be made with surgical precision. Only through extensive practice and data collection can you really begin to have any sort of accurate control over just where the round will impact.

Laminated Glass

If you practice shooting through a windshield, you’ll notice that there are usually many holes in the target. Windshields are made of laminated glass, which is especially treacherous for bullets to penetrate. The glass can sometimes tear the outer copper jacket off the lead core. This causes multiple impacts on the target. The downside is that this round deformation can reduce its effectiveness on an assailant. It cannot be overstated that you should be moving and preparing with follow-up shots on target.

Testing has demonstrated that larger-caliber rounds exhibit the least amount of shift when fired through glass. Additionally, their increased mass allows for a larger remaining core should the jacket be torn away. This should not be considered a diminishment of the 9mm round nor an endorsement for the .45 ACP. While they perform differently, it’s not significant enough to call the .45 ACP a glass round.

Shooting Through Glass -Bullet Design

Many more factors also play into this equation, such as whether the round is a hollow point or FMJ. Unless you have a stock of windshields and a variety of testing ammo at your disposal, we should review the general data and make our shots based on that. If you’re shooting out of a vehicle, aim slightly low. If you’re shooting into a vehicle, aim slightly high.

Shooting through glass is a dicey proposition at best. It is important to remember that only a worst-case lethal-force issue should drive you to it. Most importantly, though, you need to practice the art of shooting through glass. Now in all honesty, is this really going down a rabbit hole? Of course it is. However if you need to make a shot, it is always best to make the most informed shot you can.

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