This is just a suggestion, but I have personally encountered problems, as have others I know, with small pistols that have substantial recoil. It depends very much on subtle differences between hands and pistol grips, but often a magazine release can be hit by a thumb with the shooter completely unaware. Sometimes a magazine will fall free when this happens; sometimes it will just drop down slightly but stay in place, and it can make for some weird symptoms.

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Pisgah