I have an M&P Pro. Is that guiderod plastic? If it is steel, would the steel Sprinco spring be OK?
This was a response in Brian Enos' forum:
Metal guide rods are SSP legal in the M&P because the factory rod is metal. If the factory rod was plastic (ala Glock), then a metal rod would put you in ESP. Compact basepads, as far as I know, are also SSP Kosher.