What is creep tuning, and how do I do it to my dually?

I would take the time to explain it, but there are others that are so much more experienced at it. Try the search feature here, or definitely go over to archerytalk.com and try a search there. I know there were some very good explanations over there. If you are talking about a Bowtech dually, then I would start by making sure both cams are hitting the stops at the same time. Try shooting hard off the wall, and creeping forward a bit. You really can't creep too much with the duallys, since the valley is very short.

I am not positive, but if you are refering to creeping forward while at full draw, I would think your draw lenght is a bit too long.

heres a link
http://unofficialatfaq.tripod.com/creep_tuning.htm

If you are getting high and low inconsistant groups , it would be something to check . Its easy to do if you have some experiance .