I have several handguns and they seem to vary on where the point of impact is compared to the point of aim. Like my glock 22, for example. I have to aim 6 inches low to impact the target where I want. But at the same distances (7-15 yards), my m&p will be 3 inches low with a dead-on hold. And my xd-m will be a shade high with the same hold. My 1911's vary, too. Some of my guns will shoot right where I'm aiming, especially the revolvers. I've heard of six-oclock holds (although the idea doesn't really make much sense to me), but is there a way to make these guns shoot the same way with the same point of aim? It's frustrating trying to remember which gun shoots where. I spend most of my time with rifles with, so I'm not used to aiming off the target. It doesn't feel right to have it sighted in above the line of sight. Any help?