I was practicing head shots at 25 last week. I realized two things, every lapse in the fundamentals was obvious after the trigger break and factory Glock sights are awful. I redeemed myself shooting Warren tactical sights after the factory Glock. I just couldn't get my act together at 25 with the factory sights. The sight blade was as wide or wider than the head but still.
I found it was encouraging for me. Shooting at distance requires your fundamentals be solid. I'm having to learn to shoot more accurately, speed is usually not my concern at competitions. It's waiting to see if I failed to neutralize.
ETA: I brought two Glocks to the range. A 17 and a 19 to test out. The 19 had no hiccups with a mix of about 200 of Blazer brass, Remington FMJ, or Federal FMJ 115 grain 9mm. I was pleased.