M&P .45 FS loose rear frame rails

[Ben13552]

I have put approximately 1000 rounds through my new FDE .45 FS with thumb safety. It was also sent to s&w for a barrel mod. After taking it out this past weekend and subsequently cleaning it, I realized the rear frame rails are not rock solid in the polymer frame. What I mean is that there is wiggle room for the whole rear rail block to move up and down approximately 1-1.5 mm. Enough to notice with the naked eye. Did not know if this was common with the .45 FS. Just looking for some advice or knowledge on this one. I tried to explain it over email to s&w customer service. His reply was that everything was fine and there were no safety concerns. However, it just doesn't seem right. Thanks for any help!

 

[Ben13552]

to add a caveat to this...yes, the roll pin is in place behind the thumb safety through the sear block.