How are you dropping the slide?
Try locking the slide to the rear, insert full magazine, and then use the slide release to drop the slide.
If you are inserting the mag, grabbing the slide, pulling it backwards, and letting it go make sure you are "sling shotting" the slide forward.
Let the slide pull out of your hands and slam forward. Do not ride the slide forward. Being gentle with guns cause more malfunctions then being rough with them.
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