Bare shaft tuning is a debate that pops up here quite often when the new bows are purchased, and tuning starts. Some swear by it, others don' t think its necessary. I still haven' t decided myself. If you remove your fletches that would change your weight and balance of arrow. Which should effect FOC. But most I know mainly bare shaft tune at close yardages to detect arrow flight for spine correctness, and rest alignment. I' ve read a few articles, and posts here. I recall 1 article where a guy used tape at the end of his shafts to makeup the weight lose of no vanes. I also read bare shaft tuning can be dangerous if your arrows in that minimum grain to poundage catagory on the shaft charts.