Tuning arrow slap

[Fun4all]

Hmm,  I have been working on getting arrows tuned to a new Black Widow PSA recurve.  I can get a bare shaft to fly well with no noise, but when I shoot a fletched shaft there is a loud slap and the arrow shows stiff nock.  Does this on 600 spine Beman shafts to 400 spine blackout shafts, any ideas?

Bow is 45#@27"  trying to setup with 175 gr field points.  Just about every shaft the 600 to 400 shafts are shooting weak spine with shaft cut to 28".

[McDave]

I'm pretty sure what you're getting on the stiffer shafts is a false weak, where the shaft is bouncing off the strike plate so that the nock end is coming off the rest to the left.  If you're getting good bare shaft flight out of some combination, probably the .600 spine shaft, then that's where you want to be.  You might be having some fletch or quill interference with the fletched arrow, which you can correct by rotating the nock until the fletch interference goes away.

How is your form?  That can cause problems with tuning too.

[Fun4all]

Must have been the nock alignment.  I took the 600 fletched shaft shot it and slap, rotated the nock, then a nice low thump from the bow and slight stiff, but I can fix that easily.

Thanks for the fletch interference note!