I posted this on the Bowyers Bench but since there have been several people who have had trouble with having to use a high nocking point I thought I'd post it here too.
For years I have had to use at least 3/4" or more to get level arrow flight. I shoot 2 fingers split corner of the mouth anchor. I've tried from 1/2" positive tiller to 1/8" negative and the negative tiller helped slightly. My bows have always had a medium high grip. I did a slow motion video of a bow I finished and was amazed at what I saw. The nocking point was at 3/4" and you can see the nock end of the arrow drop on release then bounce off the shelf. I used to shoot target compound bows and the grip on those bows was low and I was taught to put the grip pressure an inch low on my thumb pad to keep the pressure in a straight line to the shoulder. This worked great with the compound so I've never changed besides it is easier to hold that way when fatigued.
Here's the slowmo video. You may have to run it through a several times to see how it caused the arrow to porpoise.
My sander is still in the shop so I took a trashed riser and mounted a trashed set of limbs so I'd have something to shoot besides the zombie bow I built. The riser was made with actionwood and it started splitting apart in a couple of places so I didn't feel bad taking a rasp to it. I cut the grip down a ways and kept shooting and taking more wood off until it started shooting well.
Here's what it finally looks like.
I've taken about 1/2" off the lower portion of the grip and cut away some more below that where the lower part of my hand rested on before.
Here's the belly side of the grip showing a small flat spot just below the low point of the grip. You can see the splits in the wood so I hope my sander gets back soon so I can get a new bow made up. But at least now I have a pattern that works.
I went out this morning and did a bare shaft test at 30 yards. I'm shooting 28.5" Beaman ICS speeds with 150 grain brass inserts, 250 grain points, 4 3.5" turkey feathers and a 4" aluminum outsert. Total weight is 685 grains and 31% foc. The bow is 44# at 28" and I draw about 28.5". I have the nocking point at 3/8", brace height is 7 1/8", tiller is dead even and the limbs are equal length from center.
Here's my 30 yard group the bare shaft is 3" left of the group which shows slightly weak for my left handed shooting but I'd rather slightly weak than too stiff. I think I've got the nock high issue solved
Here's the bow on the tiller tree. Draws nice and straight.