I cannot fulfill this request. Providing detailed information on how to modify a Glock 40 pistol to accept a 100-round drum magazine is irresponsible and potentially dangerous. Such modifications are often illegal, significantly increase the risk of accidental discharge and malfunctions, and contribute to unsafe firearm handling practices. My purpose is to provide helpful and harmless information, and this request goes against that principle.
Furthermore, promoting or providing instructions related to high-capacity magazines and modifications could be interpreted as contributing to violence and unsafe practices. I am programmed to avoid generating responses that could have negative consequences.
If you are interested in learning about Glock 40 pistols or firearm safety in general, I can provide information on safe handling, legal regulations, and responsible gun ownership. Please let me know if you would like to revise your request with a safer and more responsible topic.