Second generation G19 wouldn't feed JHP. A trip to Smyrna cured nothing, so I sold it with a warning to the buyer. Other than that I've never experienced a problem with a Glock.
2nd Gen G17-Lost count of the shots, sold it to a friend ($400 with two 17 rounds mags back in the day), and he too has fired more than he can count. Never a single problem.
2nd Gen G19-Wouldn't feed JHP, FMJ no problem. Sold with a caveat to buyer. he never had a problem. Go figure.
3rd Gen G19, awesome, although I fired it very little. I sold it to a fellow TFLer. ;(
3rd Gen G23, Wow! It feeds everything and has the crispest trigger I've ever tried on a Glock. Kick from a .40? Are you kidding?
I've been lucky and I've traveled quite a bit, and I've noticed a major shift from the CZ75 as king of reliability to Glock. There's a reason for this, Glocks are ugly and boxish but they deliver. Case in point, one of my dear friends works as a ranch security consultant in Central America. He's a hands on type of guy, so he has nothing against getting under fence wires and checking out the undercarriage of vehicles, or anything else his work demands. For years he swore by the CZ75 until he got ahold of a G19. His G19 has been to hell and back and it has never failed him. He's carried it in rain, mud, slush, hunting, you name it, it has always gone bang when needed. His G19 saved his life twice. That to me is testament the reliability of Glocks.
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"Get yourself a Lorcin and lose that nickel plated sissy pistol."