I just finished building some POC arrows at 28" that were from 3rivers. They are spined for 45-50# and with a 125g tip, feathers, and nock, they weighed between 415 and 430g.
Im pretty new at this but i did find that arrows from the same company again POC that were 30" and 125g points but spined for 55-60#, weigh close to 600g. Im thinking, but dont hold me to it, that the stiffer the shaft, the heavier it is.
With that being said, it will depend on what spine you get, what weight they end up. There is also a very large range for each spline, the 45-50# arrows that i just got and weighed (uncut) had weights from 308g up to 386g, but a majority of them (maybe 7-8) were between 325g and 345g.
Hope that helps and doesnt confuse you. I hope someone with more experience replies to this post cause its a good question and one that i would like to learn more about.
