Joel,
According to an old chart in a past issue of TBM,
the 230 if a 28" arrow would be for an r/d wide limbed longbow of 85/90 pounds or a recurve bow of 80/85 pounds or a narrow limb laminated longbow of 95/100 pounds. The 310 would be for 80/85 pound self bow, or 70/75 pound narrow limbed longbow or,60/65 pound wide limb r/d longbow or,55/60 pound recurve.
For arrows over 28" in length add 5# to draw weight for every inch over 28 and subtract 5# of draw weight for every inch under 28". Subtract 5# for bow quiver or heavy string silencers and if using fast-flite strings of 14 strands or less add 5# of draw weight.
I know, confusing. The number should be the deflection of the shaft but not sure. I have some at the house and I will spine a couple tomorrow and see what comes and let you know if they are close to the number on the shaft.
Danny