Arrow speed guesstimates

[Bjp67]

I am shooting a new victory rip tko arrow and I am curious if anyone has any idea what speed it might be shooting out of my bow?

I have a Mathews Heli-m 70lbs
28 in. RIP TKO arrow weighing in at 476 grs. 4 fletch AAE max stealth vanes.
Manufacturing spec on IBO speed is 332 fps.

I do not have a chronograph, nor does my local bow shop. I am curious If anyone with more experience than I have, has an educated guess.

 

[Rob5589]

Look up an IBO calculator online and enter the specs. Should be close enough for gov't work.

 

[NYyotekiller]

I’m guessing around 260fps with your setup.

 

[Farmingdale's Finest]

Somewhere about 250-255 fps would be where you are most likely.

 

[Bjp67]

I was un aware of the IBO calculator. So I went online to 2 different websites. I got 263 and 265, a little less than what I was expecting.

 

[Bowman1989]

Sounds about right I was thinking 260. Ibo is 332, you’re probably shooting 80 or 85% letoff? Take off 5-7 FPS just for that now we’re at 326, then 12-15 FPS for every inch of draw length below 30, so now it’s 295-305 roughly depending on if you’re draw length is the cam or actual because Mathews are always long. Then lastly you’re shooting 126 grain heavier arrow than Ibo standards which will cost you another 40 or so FPS.