Glocks are used for action pistol because the target is big, See how well your custom glock does at 50yds in a bullseye match. I havent seen any custom built glocks that come with a 2.5" - 10 shot group at 50yds guarantee. Just saying.
Why would I need a Glock to shoot a 2.5" 10 shot group at 50 yards if I'm not shooting bullseye? I do have a Glock with a Bar-Sto barrel that will shoot a sub 2" 10 shot group at 25 yards with 1245gr XTP's. That's plenty good enough for anything I'll ever shoot at with it!