Have you found that to be true all the time? When I first got the program I was doing something with the program that would change the spine slider but forgot what it was. I stopped using it for a while and then I sent an email tothe guy who made it and he told me thatthe performance slideronly if you want to change your set-up for a particular arrow. So, that confused me about if I was doing it right so I stopped using the slider. If that makes any sense at all? That's when I started having the issues with the program spining the same way it used to for me.

Your last sentence mayexplain an issue I was running in to. I would change it on the equipment set-up tab and noticed that I couldn't reach an IBO low enough for my bow.Some things just are not explained out well enough evenby the guy who wrote the program.

Thanks for the info. I'll try it out.

The program is called OnTarget2 and a trial version can be found at www.pinwheelsoftware.com

TFOX is 100% correct about this and I have found it to be true all the time and with different arrows. I have found that the performance slider is like a "setting" for a particular bow model. Once you have measured the speed of an arrow through a chrono and adjusted the performance slider to get the correct calculated speed there will be a value in the performance slider that you can use for that bow model on any future calcs. I have two identical bows except for DW, one is 60# and one is 70# and the same performance slider number works with both (-85). Kudos to TFOX for figuring that out!

I ran into problems with the program being correct when a particular bow didn't reach the performance goals set by the manufactuer,for whatever reasons.I would try and change the ibo speeds to calibrate it and the spine would not change.I ran it all the way up to 400 fps and spine did not change so I contacted ot2 and I was told that they did not use ibo but they used cam style to set spine.


I had to figure out the performance slider on my own which really upsets me that they can't explain how to use their product.[:@]


Archers Advantage uses IBO and if a bow doesn't reach the numbers it is supposed to,just type in what it shoots and you are done,no quess work.Not to mention it is much easier for the average guy to grasp.SO,if I am asked from now on which program I recommend for spine calculations,I am with AA all the way.

OT2 has some nice features but is a pain in the you know what to use.

do you think .300 spines would be better for my set up, than .400?

I know it was suggested to use .360 spines.

I'm thinking about getting a chrono, and maybe in a bit I'll check back with some updated info. but considering having new arrows built.

I'd like to shoot 70# with my drenalin 28" draw 65% let off.

28" arrow shafts, 100gr broadheads.

.300 will be very overspined. I use a 120 gr tip and would have to go to a 34" arrow for a .300 arrow to work.

I've been playing around with OT2 and I still think you can use the .400 with your bow even at 70 lb. Your IBO will not be 320 fps with a 28" DL and therefore your performance will drop.As I move the slider down the spine goes up for your bow using the Carbon Tech Whitetails in .400 spine. If you wanted to make sure about this just add a wrap to increase spine. I'm guessing that your speed will not be over 280 fps with a 28" DL even with that arrow. Therefore, if your speed is slower than what I've used the spine will be stiffer than what is shown.

sounds good, and the whitetails I currently use are the .0015 straightness, I think im going to pick up another 6, and do it up.

Thanks for the help/info.

If / When I get a chrono, I'll report back with some speed details.

Anyone have a chrono they like?

Chrony BrandF-1 Masterwith the remote display seems to work well. It's the green model and the good thing about not having the display right on the model is that if someone would accidently shoot the front of the chrony with an arrow it will not destroy the display.

I found 1 online for under $90 last year. It will work for guns too.

You could also add the McKinney nock bushing to stiffen it up a little. I can see in davepjr71's screenshot that he has it in there although you may not be using it so be aware that his numbers include it. Also, the nock bushing weighs in at about 14 grains instead of the 12.10 that it shows. I use Carbon Tech arrows and have weighed the bushing.