Unfortunetly no. The Magazines are designed to fit in the same magazine well, and are the same length, but that's the only similarities. The .40 magazine has a reduced interal width due to indents that run throughout the length. The followers are different, and the lips are different. You can, however, buy a conversion kit so that your frame can be .45 and .40 capable. You would have to change out the top end and ejector when you wanted to change over.
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Really interesting....Don't ya think??