In this video, LAS TechXpert P.J. Reilly addresses the difference between arrow weight and arrow spine.

An arrow's spine determines how much the shaft flexes when it leaves a bow. Archers want their arrows to flex some, but not too much.

Arrow weight refers to how much the arrow actually weighs. That weight can change as you look at arrows of different spines, but simply choosing a different arrow spine in order to change your arrow's weight is not a good idea.

We sometimes see bowhunters opt for weaker arrows when they want to cut arrow weight, or choose stiffer shafts if they want a heavier arrow. Either can cause problems with accuracy, especially if a fixed-blade broadhead is added to the shaft. Such broadheads tend to magnify flight problems.

Lighter arrows fly faster than heavier ones, but heavy arrows generally result in better penetration. Depending on what they're hunting and where, bowhunters might prefer a heavy arrow or a light one.

Bowhunters choosing an arrow should stick with the spine recommended by the manufacturer. That recommendation will be based on draw weight, arrow length and point weight.

If bowhunters want to change their arrow's weight, they can opt for heavier or lighter shafts without changing spine. They can also increase or decrease point weight, but then that could affect the manufacturer's spine recommendation.