PDA

View Full Version : Firecat questions



hotrod26
07-14-2011, 01:55 PM
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.

Speedykills
07-14-2011, 02:07 PM
For what its worth ive got a 2008 firecat pro x and at a 29DLx64#DW with a 372grn arrow i was shooting 285fps through chrono,that my hunting setup.So i would say your about right or close to it.
If you want to go faster get a lighter arrow and up the draw weight.

Hutch~n~Son Archery
07-14-2011, 02:09 PM
For what its worth ive got a 2008 firecat pro x and at a 29DLx64#DW with a 372grn arrow i was shooting 285fps through chrono,that my hunting setup.So i would say your about right or close to it.
If you want to go faster get a lighter arrow and up the draw weight.I agree

Hutch:cool:

hotrod26
07-14-2011, 02:19 PM
Not what I wanted to hear, but thanks guys!

Hutch~n~Son Archery
07-14-2011, 02:22 PM
Drop your field points down to 85grns. Up your bow to an even 60 and see what the will give you, on the calculator.




Hutch:cool:

Speedykills
07-14-2011, 02:23 PM
Not what I wanted to hear, but thanks guys!

You would be suprised what a inch and more draw weight will do.Also i would check timing and axle to axle length and brace height to make sure everything is in spec so no string stretch has accured.You can loose speed that way too.

bfisher
07-14-2011, 02:34 PM
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).

Destroyer
07-14-2011, 08:08 PM
Its somewhat easier to work it out going to IBO than the other way around.

So we have 57#, 28", 380 gr = 252fps

IBO (5 grains per pound) at 57# = 285 grains. Which means 95 grain less and at least a 25 fps increase. We are up to 277fps. Add another 26 fps to get to 30", now 303 fps IBO. Add the usual IBO 'mythbuster' value of 20 fps and we get 323 fps IBO. Still a little short so there could be some extra fps missing but its not far off.

I would be a little disappointed at the speed your getting too btw. ;)

Speedykills
07-14-2011, 08:52 PM
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.

Your DW isnt helping either.

Spiker
07-15-2011, 06:22 AM
'09 Firecat
62# dw
29" dl
385gn arrow = 294/295fps thru chrono anytime.

Speedykills
07-15-2011, 09:44 AM
'09 Firecat
62# dw
29" dl
385gn arrow = 294/295fps thru chrono anytime.

This shows how chrono arent built the same,i have more draw weight lighter arrow and im getting 285fps.It's either the bows or chrono that isnt consistent.To many things come into play.

Destroyer
07-15-2011, 03:51 PM
I don't think its the chrono's that make the difference here.

Speedykills
07-15-2011, 07:24 PM
I don't think its the chrono's that make the difference here.

Would you explain yourself!!!!!!!!!!!!!!!!!!!!!!

Destroyer
07-15-2011, 08:51 PM
Would you explain yourself!!!!!!!!!!!!!!!!!!!!!!

Bows vary in speed due to manufacturing quality or a lack of it, some are setup different as far as wheel rotation or tune. And some bows aren't exactly the same, different strings with lower strand count and lighter materials, etc.


So basically, 8.4 fps error.

The accuracy + or - can play its part but for someone to have each shot consistently at the extreme end is a bit much to pin on a accuracy error.

Speedykills
07-16-2011, 03:48 AM
different strings with lower strand count and lighter materials, etc.



Maybe he uses wicked1 strings..........................................: p

Spiker
07-16-2011, 05:25 AM
I've shot my FC and most of my other bows thru my chrono and thru one at a shop 45 miles away and only get 2-3 fps difference.

hotrod26
07-16-2011, 02:20 PM
Sonny, sorry I haven't got back sooner with answers to your questions.

1. The timing looks good
2. Using a QAD dropaway
3. Center shoot is good, shooting bullet holes through paper
4. Scale used to weigh arrows is the one I use to weigh all my arrow components
5. Yes the scale used to check DW is correct and to check we used a second scale.
6. Shot through chrono 6 times, 4 were duplicate and 2 were 2 fps faster at 254fps
7. Used a led light kit on chrono inside a garage with normal lighting.

One thing I have found is that the ATA is 32 7/8" and according to Martin website it should be 32 1/4"
also brace height is 6 3/4" and should be 7". Would this make a difference in the speed? Also I know just enough about bow tuning to be dangerous so what would I need to do to decrease the ATA and increase brace height.

Destroyer
07-16-2011, 04:32 PM
In other words, you're right.

I like that, sounds nice Sonny......:p

Arrow Splitter
07-16-2011, 04:58 PM
I like that, sounds nice Sonny......:pThere should be a puke smiley on this forum.:p

Destroyer
07-16-2011, 05:18 PM
there should be a puke smiley on this forum.:p

rolf!!!!!!!!! :D