I built a new string for my bow at the last minute and just got done tuning it. My arrows at 30 yards are hitting shafts together and at 70 yards I can hold a 2.5" three shot group with one of them being a broadhead. The problem is at 50 yards, my groups open up to about 6-8 inches. I can only assume that it is me, shooting the middle pins, that I have a problem with. The arrows are on a path and if they are on at 30 and 70 then in the middle they should also be right on. Just to rule out any bow tuning issues, is this the general consensus.