I had some of the same doubts on ammo so I e-mailed S&W tech support and asked if I could safely shoot the Speer lawman 124 as range ammo and either the Speer Gold Dot 124 +P or the Hornady Critical Duty 135 +P as carry ammo and he answered back that all of those were fine. No problems shooting +P.

This is with an M&P9c.