
Originally Posted by
hotrod26
I have a 2010 Firecat TR2, DW 57# DL 28" shooting a 380 grn arrow and I am only getting 252fps. Any of the guru's on here have an idea as to why it is so low. If my calculations are right I should be getting around 272-275fps. Have ran the numbers through several calculators on the internet and they all say I should be getting from 270-278fps.
I have had or do have several bows with the Cat/Nitro/Hybrix cams and I'll let you know a little secret. When you plug the IBO speed into your calculator reduce it by 20 fps. IMO, based on actual chrono results the IBO speed are inflated by that amount. And if you want real numbers then use a real chrono. Every on-line calculator I've used has produced speeds about 15 fps faster than actual chrono results.
In fact, I just used the Backcountry calculator I just worked up my specs. IBO speed-335fps, 27" draw, 230gr. arrow. Calculator says my arrow speed is 319fps. My bow shop's chrono says just about 275 fps. Which is right? Sad to say, but I can definitely tell when speeds are around 300 so I'm believing the chrono.
In your case, if you start shooting 5 gr/lb you'll have an arrow 95 gr lighter. That will boost the speed up about 40 fps or a little more--close to 295-300. If you're just going to hunt with it then 252 fps is plenty. I killed the majority of my deer with compounds shooting less than 230 fps and some of them at a measely 190 fps or so (many years ago).
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