The weakness of carbon arrows is impact damage to their side walls. The thinner the wall, found in lightweight shafts, the less sideways impact they can handle. If an impact goes unnoticed then the shaft can break at this point. Sometimes the shaft will developed a raised ring around it. This is where the carbon has failed and the arrow has compacted on this spot. If the arrow is flexed at that point then shaft will break there. Because of this arrow manufacturers recommend flexing your arrows each time before shooting them. This will ensure you will find a weak point but I do not know anyone who does this. It does pay to inspect all of them before you start shooting. If you’re practicing with broadheads then check your arrows after shooting them as it doesn’t take much for a broadhead cut down the side of the shaft and severely weakening the arrow. Arrows can break when shot if they have been weakened. We recently had one in the shop break inflight when a crossbow was being test-fired. Luckily no harm was done.
The unseen failure of a carbon arrow is the one which offers no danger to the shooter but destroys their accuracy. It is the loss of arrow spine. Much like wooden arrows carbon arrows are made up of fibres and after prolonged use or suffering a hard impact these fibres can break down. When this occurs the arrow spine begins to weaken. As most hunting bows deliver a substantial amount of energy having the arrow spine weaken will cause it to flex differently coming off the bow. With a broadhead on the end of an arrow this change will cause the arrow to hit outside of your usual group. Once again the quality (and cost) of the arrows determines if and when it occurs. Sometimes the spine of cheap shafts will vary within a batch of new arrows. It is a good idea to number your practice arrows so you can easily see if it is the same arrow which is the odd one out of the middle.
I like to have all of my hunting arrows in perfect condition and will pass any used ones into my practice arrow bin.
Shoot to Kill