I reload for my G19, G21, G23, G30, G34 (9mm, 40 S&W, .45 ACP) using different bullet configurations and weight (FMJ, Copper Plated, HARDcast). I usually use W231 powder for all of them and I use medium high powder charges (minus 10 to 15 percent of the max load for the given caliber). NEVER had any issues with any of my Glock pistols.
My first Glock was the G23 (first time they came out in the 80's), a 40 S&W, fed it 95% CAREFULLY assembled reloads and 5 % factory loads. Never had a problem.
So, I believe, the secret is feeding them with sane and carefully assembled rounds.
My experience, so I'm sharing what I went through.
Ninja45