I just got back into archery hunting this season after taking a few years off. In the past I always used aluminum arrows, this year I bought a bow that came with carbon arrows. I thought about changing back but decided to try the carbons that came with the bow. I've been impressed with them on the target range but haven't had a chance yet to see how they perform on an animal. Anyways, too my question, I understand the numbers on an aluminum arrow but carbons are different, the arrows that came with my bow are marked 60-75 while a buddy is shooting an arrow marked 340, can someone give me a quick education on what these numbers refer to? I did a quick search but couldn't find anything, thanks.