Hello, great question, I have a 9 shield, MP9c, glock 19, MP40c, glock 23, I mainly carry the glock23, the reason is the mag capacity and the reliability of the gun and mag. I purchased full sized magazines for the MP and the glocks, the mps have the little spacer that fits the mag to the frames. I did that to the 9mm also.
Good luck
SEMPER PARATUS

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