Even thou you might be down by several per mag, the reliability of a Glock & the usual incompetence of the reloading habits of the majority of Open shooters tends to level the field ! As soon as a .38 or 9 shooter has a malfunction & ejects 1-2 rounds correcting it, he's lost time & ammo capacity. Meanwhile, the Glock just keeps running.
I saw this in a match my son was shooting, using his G24 in open. 9Major wasn't legal yet, so he was the ONLY .40S&W cal gun in the match in Open. One stage stands out, 32 steel poppers, basicly a balls-out shooting stage. He finished 5th on that stage, behind 2 GM's, 1 M & 1 A shooter. Bad choice of where to make his mag change cost him 2 places. But his G24 never bobbled. He beat several GM's & M's, as well as everybody else. He was shooting UNCLASSIFIED at the time, not having enough matches scored to be classified (he's now a very high "B" shooter).
Bottom line....everybody behind him had ammo related gun malfunctions, due to sloppy reloading quality control. Most Open shooters get their "SUPERGUN" and think it's a cure all. So don't rule out a Glock as opposed to a 1911/2011 type pistol.
(I'm currently building him a 9Major based on a G34 type pistol, & have been experimenting with 9Major for almost 8 yrs. Use it in my Production G34 on heavy steel stages for R&D) Oh yeah, my "normal" 9mm production ammo runs a PF of about 148-150. We shoot real-world ammo, not gamer loads in anything. When I used to shoot my G20 in Production, I was using a load with a PF of 214 !