Buddy is shooting an entry model PSE with a whisker biscuit with a release and carbon arrows. Arrows are within the spine range for his poundage, and he's using 100 grain tips. Has pins set at 20, 30 and 40 yards. He's right handed and right eye dominant.
At 20 yards he's grouping dead center. At 30 he's high and right. At 40 he's higher and righter. He claims arrows are flying straight, no fishtailing or porpoising.
I haven't seen him shoot yet, but based on this I'm scratching my head. If it was a spine issue, I'd suspect he'd be shooting left (he's at the low end of the spine range with his bow poundage). If the rest was way off I don't think he'd be getting the good flight he's claiming, nor the consistent dead center 20 yard grouping.
I do plan to check to make sure his 20 yard pin is his top one

, but other than that, any ideas what to look for?