Magazine will not release with slide locked open after the last round fired. This has recently started after firing several rounds . If a Magazine issue have new springs and parts to install.

Check for damage to the ejector, or the top, left side of the magazine that lies under the ejector when it's inserted.

You may also need to disassemble and clean the magazine release plunger, plunger recess and spring. The spring can get compromised by rust, and the cavity can collect old lubricants, etc.

Check the magazine shell for evidence of damage....usually can be seen as "shiny" spots on the outer surface of the shell. The interior of the magazine cavity in the gun can also become dirty, causing the magazine to hang up.

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Ret. LE, FA Instr, S&W Armorer

Thanks armorer951