View Full Version : 2001 Phantom Performance
05-30-2011, 09:06 AM
I have a 2001 Martin Phantom with Fuzion cam, 28" draw, set at 60# draw weight, 65% let off.
My question is regarding expected performance. I have chronographed the bow and with a 421g arrow the speed is 218fps and with a 520g arrow 202fps. This speed is significantly less than I would have expected based on the IBO rating of 301fps with a 350g arrow at 30".
Is it time for new limbs? A new bow? Does the 2" shorter draw make a big difference in speed? Or is the rated performance always significantly less than real world performance?
Thanks for the Help
05-30-2011, 10:46 AM
What is the A2A? What is the brace height? How old in the string set?
If the specs are all good. Then the next thing to look at it the weight of the arrow.
05-30-2011, 04:33 PM
Does the 2" shorter draw make a big difference in speed?
Yes, about 10 fps for ever inch you drop. And about IBO speeds, I usually drop 20-25 fps to get a more 'realistic' speed. With 60# you can add at least another 10 fps drop.
05-30-2011, 06:13 PM
The IBO is figured with a 350g arrow at 30" at 70 lbs not 60 like you are shooting. I thinks this is where Destroyer was going with the loss for shooting 60 lbs.
It could be a tuninig issue, are your fletchings hitting the rest anywhere. Do you have a lot of access merchandise on your strings. string silencers, peep tubing, and even d loops can slow down your speed a little. but don't worry too much. In hunting applications, if it is quiet, and accurate, even the slowest bows are deadly. I started with a Darton Trailmaster back in the 80's and it had an arc at 20 yards and still didn't lose a deer with it. Even killed a black bear, complete pass through and the thing maxed at 55 pounds if i remember correctly.
05-30-2011, 08:23 PM
And 421 grain arrow works out to 7 grains per inch @ 60lbs. To go IBO you need to drop that to 300 grains, 120 grains over which would drop you even further, maybe another 20-24 fps at least not taking into account the bow efficiencies.
So IBO of 301 fps, your bow specs will drop the speed to a theoretical 227 fps max without anything on the string. This is pretty close to what you have.
I started with a Darton Trailmaster back in the 80's
SL20 ? Started with something similar I think but can't remember the model.
05-31-2011, 06:02 PM
Have the same bow. Don't know the weight of my arrow but it's set up for hunting and last I had it checked was right at 267. Nothing on string but peep(no tube), and loop
05-31-2011, 09:57 PM
You are only 5-8 fps slower than average with that weight arrows.
A really good tune will bring you up to spec or a bit over.
Lighter arrows will take you higher.
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