Remember that the gun was built with loose tolerances--VERY loose tolerances. And, it uses those tolerances very well to function better than almost any other semi-auto pistol.
However, that does not mean that it can't be accurate. My G22 is one of the most accurate pistols I own. It has had a full length steel guide rod installed, and a 4 lb connector. I can hold the center of a B27 silhouette at 25 yards easily. In fact at our last qualification, I put 30 rounds in a group about 2" big at 25 yards.
Your best bet for accurizing is to have a good barrel custom fit. Bar-Sto makes aftermarket Glock barrels with conventional rifling.
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Happiness is a 200 yard bughole.
I'm not sure what you are expecting, but I doubt anything will give a significant practical improvement over that.
Good Luck, MM