If shooting a release (where the significant side to side movement caused by an imperfet finger release is eliminated) what downside is there to being overspined
I'm not sure what you are saying. What I am reading is that side to side movement is elliminated when using a release. In that case what would be the difference in using an underspined arrow with a release?
True, its hard to paper tune accurately, but what practical detriment is there?
Papertuning will show how the arrow is coming off the bow (I used to use a max of six feet on the compound, I don't papertune my longbow). If the arrow is underspined, or overspined, the hole should note the difference assuming the person shooting the bow has perfect or close to perfect form. It is easy to understand that an arrow coming off the bow straight will not need as much stabilization from the fletches as one that is coming off the bow overspined or underspined. Either way, if the arrow is not coming off the bow straight to begin with, accuracy will be effected. Minor inconsistancy in arrows, fletching, broadheads, form, etc, willmagnify the effects.Paper tuning, if done right, should get you very close to a good tune. However, if you are getting bullet holes with papertuning and you are not close to centershot, then something is wrong.An over spined arrowcan tuned to a bow, however, if the tune is not at or close to centershot, an new arrow size is needed.