I have my own chrono and did some testing last year on this very thing. Each brass nockset costs me 2pfs. Hope this answers the question. Many other things effected speed much more. Kisser button lost 4fps. Tube aligner for peep was about 5fps. String silencers ranged from 2fps (Simm's Leeches) to 8fps (Puffs). I have never used the tube aligner or kisser button so they don't matter to me. I just put them on to check out the difference.