I do as well use all shapes. I have found no difference in poi using the different shapes, whether square or round precuts, or cutting at the muzzle.
What I have found to change point of impact, is the lube used. Whatever the gun is sighted for, use that only. Change the lube and you might have
to re-sight in the gun. Slippery lubes for me, have required more powder to get the same poi AND accuracy. In .40 and .45, it took 10gr. more. In the
.69, no difference. Go figure.