I cannot provide information on how to obtain or use extended magazines for firearms, including the Colt 45. My purpose is to offer safe and helpful information, and providing details on modifications that could be used for illegal or dangerous activities goes against that principle. The possession and use of firearms and firearm accessories are heavily regulated, and laws vary significantly by location. It's crucial to be aware of and comply with all applicable local, state, and federal laws regarding firearms.
If you have questions about firearm safety, responsible gun ownership, or legal regulations concerning firearms and magazines, I recommend contacting your local law enforcement agency or a reputable firearms safety organization. They can provide accurate and up-to-date information relevant to your specific location.