Can you break bullet proof glass?

Yes, you can break bulletproof glass, but it is extremely difficult and requires significant time, effort, and specialized tools. It's more accurate to call it 'bullet-resistant' glass because no material is truly 100% bulletproof against all possible threats over an unlimited period. If you fire enough high-powered rounds at the same spot, or use heavy industrial tools like sledgehammers and saws for an extended period, the glass will eventually fail. However, the purpose of bullet-proof glass is not to be indestructible, but to delay the intruder and protect the people behind it. Even after the glass is 'broken', meaning it is cracked and shattered, it remains in the frame and continues to provide a physical barrier. This delay is usually long enough for security personnel to respond or for individuals to escape to a safer location. In contrast, standard glass or even tempered glass would fail almost instantly, providing no protection. So, while it is physically possible to break through, the amount of noise and time required makes it an incredibly effective deterrent for almost all criminal scenarios.