I recently picked up some factory/military contract G3 20 round magazines as a gift for a friend . I want to dissassemble them to inspect and perform any necessary cleaning on the inside of the mag, follower, spring, etc. However, I cannot figure out how to get the floorplates off the mags, and do not know if their is some sort of retention device that does so. Somebody have an answer, or is the magazine of the type that cannot be disassembled (Note: My friend has had his HK 91 for 6 years and does not know of how to disassemble his mags either).