ORIGINAL: KLS
I've noticed that the higher the number the less spine the arrow has, 500 being weaker than 300, and the weight per inch also increases from higher number to smaller, but thats about it for "in general" information...
This is true for Beman and Easton(same company) but not for other manufacturers where spine increases with a higher number. It certainly isn't a hard, fast rule across all manufacturers.
ORIGINAL: KLS
so say in the case of bemans ICS carbon arrows, are they all 22/64"? from what I've kind of gathered through various reading the beman thunderbolts are basically bemans ICS shafts, so would the 400 beman ICS camo hunter shafts cut down to 20" be the same as the thunderbolts? or 350's? or 300's?
I do not know what the diameter of the Beman ICS shafts actually are but they are less than 22/64's OD. Why don't you just getthe Easton Powerbolt shafts? They are already cut down to 20", will be the correct spine and are 22/64's OD. You can find them pretty easily for around $36-&40 a dozen which is much cheaper than buying full length arrow shafts and cutting them down.