Spent some time today shooting my Arroyo - talking myself out of selling, maybe - but I have an odd thing happening.  The bow is 51@28, and I'm drawing 28, shooting split.  It likes 55/75's with 125 gr points and bareshafts well with these.  Trying some 35/55's which would logically match the bow better.  They fly ok but impact lower which seems odd since they are lighter.  I'm seeing signs of hard impact on the shelf, too.  Nock point?

Only way to tell is change the nocking point...not sure what that would accomplish though when you already have the 55/75 flying well

DDave

Good point

Arrow length can trump a lot.  Are these shafts full length and both the same length?

Shoot them thru paper I swear by it and it will tell you what is going on.    Widow

Old dog they are close but I haven't put a tape to them.  I'll check that today.

What happens when you shoot a few bare shaft 3555s with a few fletched 3555s?

I can shoot fletched .500s out of my 50# recurves and they fly ok with field points.  Bare shafts or broadheads not so much.  The .500s are so weak for me and my bows that they plane so hard I can't keep them on the target at 20 yards.  Your setup with the 5575s seem like a reasonable arrow for your setup.

Even though lighter it might be that the .500s are so weak and the feathers have so much stabilizing to do that you are loosing velocity, resulting in the lower impact point.  Any contact is also going to affect your arrow flight and velocity.  An overly weak shaft can cause all kinds of issues.

Easy, exactly what happens when I shoot bare and fletched 3555's.  The group blows up.

I'm just going to fletch up some 5575's and shoot 'em.  They are quieter, also.