Accuracy, or more properly precision, is more dependent on barrel/projectile match and the quality of ammunition used than any generic bullet weight generalization. While a certain weight will likely shoot better in your firearm the only to know is trial and error short of using a known combination. Even when using a known combination most competition shooters, or their gunsmiths/armorers, extensively test. For example, the AMU uses a KKM 1-18 barrel with made to spec 115gr Atlanta Arms ammo in their Beretta's, but you can be sure each one of those guns is tested hard before being cycled into competition.
Will you see any difference at 7yd, not a chance. 20yd, maybe. 50yd, yes, but only if you can consistently hold a 3" group at that distance anyways. I certainly can't.