Thought i'd give you a first hand report on a busted slide--i've got a 17L that i got used probably 10 years ago and i had 2 50 cal ammo cans full of 147 gr lead rounds that i loaded to shoot in a subgun--well i had a bunch of it left and i forgot just how hot it was but anyway one day while shooting the 9mm 17L the accuracy went crazy......Looked below the ejection port and the crack was there--sent it back to glock and got it back with a new slide sometime later--no charge--Dick