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Posted: 5/18/2012 5:27:49 PM EDT
| new AR 15 S&W M&P 15 safety selector switch is sticking and hard to engage..I put in a clip and cock it and the switch moves smooth.after dry firing it sticks and is hard to move |
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Yep. bottom of the hammer is oblong lobbed, and with the hammer in the uncocked position, this bottom lob of the hammer slightly presses the top front of the trigger to move it slightly backwards, and with the trigger in this position, the select flat to round section can not clear the back of the trigger tail to put the selector in the safe position.
As for why this is, if the selector was able to be set to safe with the hammer uncocked, then when you tried to charge the rifle, the selector would block the trigger front being able move front downward the needed amount to allow the hammer sear to clear the trigger sear as then went to engage. To see this, with the hammer uncocked, slowly go to pull back on the charging handle, and you will notice that the trigger is moved back past what would the normal hammer cocked position to allow the hammer sear to clean the trigger sear, then the trigger moves slightly back forward as the two have engaged, and the point that now the selector set to safe will prevent the trigger from moving back. |
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