Arrow grain
#3
Join Date: Feb 2006
Location: Kodiak, AK
Posts: 2,877
RE: Arrow grain
400 is the deflection rating of the shaft which tells you how much (or how little) spine it has. It is a measurement of how much it bends from its horizontal axis when a standard weight (which I forget the value of: 1 lb?) is hung from the center with the shaft supported over a span of a standard distance (which I've also forgot, 28"?). If all manufacturer's shaft spines were measured this way it would allow you to compare or switch from one shaft to another without the guesswork of getting the right spine. I think the only ones that use this standard are Easton carbons and A/C's and the Bemans. For weight, I think the Bemans print the grains per inch on the shaft. Multiply this by the length of your shaft. That will be the shaft weight and you'll have to add the nock, insert, fletching, cresting and head to that to get your arrow weight.