My bareshafts are diving towards the ground at 25-30 yds.. Fletched arrows appear to fly OK, though I can occasionally see some porpoising. Shooting split-finger, cock feather in.
This indicates a nock high condition, yes?
Well yes and no! Confused? It can be frustrating at first, but if your nock pt is too low to begin with it can cause the shaft to kick off the shelf of the bow and give you a high nock kick in the arrow. Best to start out very high and work your way down. I normally will start at 1in or so and go from there since I have had some bows that tuned out at 7/8in nock height. Most of my BW's normally tune around 5/8in but my Bob Lee's were around 1/2in. And be sure to hold the bow straight up and down when you bare shaft tune so as to not induce some centershot or spine issue into the shaft while working on your nock pt. You can also tell a low nock position on the arrow if you are getting excessive wear on your hen fletch against the shelf. Good luck! Mark
I have had this happen many times with off the shelf bows shooting split finger. If I change to 3 under the problem goes away. I usually can never fix it with nock point adjustments. It could be a bow tiller issue vs type of release/anchor issue.
Bareshafting is really only for achieving correct arrow spine anyways and if your arrows are shooting correctly down center and not planing left or right I wouldnt worry about bareshafting anymore. Just tune the nocking point until your fletched shafts are shooting correctly.
Oh yeah... One other thing you can check is nock fit. I believe a too tight nock on the string may cause this sometimes too.
I think a nock-high condition that causes your bare shafts to impact somewhat lower on the target than your fletched arrows can be an indication that your string nock needs to be lowered (unless it's already too low, as Mark said), or it can be an indication that your forefinger is pressing down on the nock when you draw the arrow, causing a rebound off the shelf, due to too high elbow or some other form issue.
However, I think extreme nosediving into the ground in front of the target is more of an indication of a tillering problem. I once had a Hoyt Gamemaster that had that problem, and could not be tuned to shoot off the shelf, although the bare shafts flew fine off a rest. I eventually sold it, since I only want to have bows where bare shafts fly well off the shelf. As Tom mentioned, this may not be as important as we make it out to be, but we are only in this for our own enjoyment, and I don't think I could be happy with a bow where bare shafts don't fly well off the shelf, particularly since there are so many bows out there where bare shafts do fly well off the shelf.
Sometimes the tiller can be such, in combination with finger pressure location and bow hand pressure location, you can never get rid of it entirely but you can find the spot that's best by looking at where bare shafts (or wide broadheads) group in relation to fletched field tips. Trying to get rid of "kicks" be they up/down/left/right as often as not are excercises in futillity....O.L.