What can break bullet proof glass?

Breaking bulletproof glass requires a massive amount of concentrated energy or specialized equipment. Common methods that might breach lower-level bullet-resistant glass include high-powered rifles (if the glass is only rated for handguns), repeated strikes from heavy tools like sledgehammers or axes, or industrial cutting tools like diamond-tipped saws. It is also important to note that most bullet-resistant glass is rated for a specific number of shots; for example, a UL Level 3 window might be tested to stop three shots from a .44 Magnum. If a fourth or fifth shot hits the same area, the glass may finally be penetrated. Additionally, extreme heat from a torch can eventually compromise the plastic interlayers that provide the glass its strength. However, for most real-world scenarios, bulletproof glass is virtually impossible to break through quickly or quietly. It is designed to withstand the types of attacks most likely to occur in a robbery or active shooter situation. The 'weak point' is often not the glass itself, but the framing or the surrounding wall, which is why a complete security system must include reinforced components for the entire opening.