Both kahr & M&P shield's are rated for +P and both have supported barrels... I wish people understood the difference between the two different type's of barrels. The info is easily obtainable online (forums are not a credible source of info BTW)

My CM9 didnt lock back after the last round up until I ran a couple boxes of ammo thru it... Clean & lube after each range session & you'll be fine. congrats on a purchase of a fine weapon.