I just checked the 2 arrows in question on my spine program and your Blackhawks are almost the exact same spine at 31" as the 300' s are at 29" .The 300' s are stiffer but only a very small amount.It really shouldn' t make that much of a difference.


That being said,I would cut them to about 1" in front of the rest.I would then cut the fletching off and start paper tuning this way.That will eliminate any problems associated with the vanes and will ensure that you are getting as good of a tune as possible without letting the vanes takeover.If you get it tuned with no fletching and then fletch.You will know that there is contact and you can go from there.