So now I'm an expert on Xbows after three weeks....Bolts are normally 22/64" on the OD..hence 2219...22 being diameter and 19 being wall thickness...there higher the number the thicker the wall. Excal offers bolts in sizes 2216 and 2219....carbon bolts are also 22/64 on the OD. As to lenght ; doing research..I noticed thatevery bow is different ,seeing four different bows from one maker , all stating the same lenght bolt, on one model thefield pointjust cleared the rail on another the field point extended into the stirrup , so can you shoot a 20" bolt in a bow that came with 22" as long as it clears the rail???...........do I ask too many questions..64