You calibrate the software is over a Range of arrow weights (gr/lb) and not for a specific arrow.
For the VPG, shoot one arrow at your max DW that is close to 5 gr/lb and then one that is 7 gr/lb or more. This will ‘adjust’ the software for the bow’s efficiency, and yield better results for any arrow between those two weights.
If you measure everything on the bow that is asked for….not just go with the standard stuff that is put in the program, it will be crazy accurate. I put everything in for my Apex 7 and it came out as 304FPS in On Target, I got 305 when I measured it. WOW
Just got a new dozen Beman ICS hunter 340’s and here is what I did. I measured each arrow length to the nearest 32nd of an inch, weighed each arrow, each nock and each insert and took the average of each of them and that is what I put into OT2. I made one arrow and it weighed 2.3gr more than what OT2 said it should!!! Pretty awesome. Question should I shoot a light arrow and a heavy arrow to update the efficency rating? should I activate more than one of the efficency tabs? That will make things better right?