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How to figure down range velocity and energy??

Old 06-18-2006, 06:02 AM
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Nontypical Buck
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Default How to figure down range velocity and energy??

Shooting a Pheonix with 20"EastonCarbon Power Bolts which I think are 400gr. and using 100gr. points. In the best of all worlds I could be shooting 305 fps following apparent manufacturers recomendations of minimum arrow weight. Do they have a spine recomendation? Without a Chronagraphcan I estimate arrow speed ect. downrange? Oh yeah. How much do the carbon arrows that came with the right stuff pack weigh? I am not really concerned about top speed as I can't see the beast ducking an arrow at 30 yards and short range foot pounds are nice too.
Is it wrong for me to love my bow this much?
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Old 06-18-2006, 08:39 AM
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Default RE: How to figure down range velocity and energy??

If you are going to be able to figure energy, you must have a chrono, the formula is velocity squared times mass(weight of bolt) divided by 450240 that will give you ft/lbs, all things being equal, that will give you penetration....Do not be fooled by the makers claims of speed, most of "them" lie to bring in more customers............The ones that have been the closesest to their claims have been Excalibur and Bear both of these bows have actually shot faster for me thru the chrono.If fact both shot(Bear340&Exomag) almost the same, both were over 370fps with Golt Tip Lazer2 bolts with carbon inserts and carbon bolt endsand 75g points.......
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Old 06-18-2006, 09:01 AM
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Default RE: How to figure down range velocity and energy??

Don't quote me but i think i read that Excal carbon II's weigh about 430gr. with the 100gr. pt. I spect they put 75gr. head on to get the 305 from phoenix. I have the Phoenix myself and shoot 2219's with 100gr heads and i est.272 in speed. I don't have a chrony,but that would be a fair call on my setup. It will get'em from 1 to 40 yds.[]
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Old 06-18-2006, 11:12 AM
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Default RE: How to figure down range velocity and energy??

I can shed a little light on this one. Excals stock arrows weigh 350 gr w/ 100 gr points.Using 75 gr points on them is not a good idea because you are going to be under their minimum weight requirements and it is really bad for your bow.

Jq7: Was that a typo on "carbon inserts"?? I am/was not aware of any inserts that are not either aluminum or brass.

Planter: you can come real close to figureing your speed by taking the advertised [and true] 305 fps and subtracting for changes. Example: going from FFF string to Excel = minus3-5 fps. Using a heavier arrow, subtract another 1 fps for every 5 gr increase in arrow weight. I'm shooting 20" LII's, 4" vanes, brass inserts, 100 gr points, weight 431 gr. w/ Excel string in my Phoenix. So, I've lost about 18-22 fps, which is what my "speed ring" on V-zone agrees with. Trust me, you'll never miss those fps and the benefits of those 431gr. arrows are numerous. As far as I know there is no spine issue w/ carbons. Hope this helps.
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Old 06-18-2006, 12:15 PM
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Default RE: How to figure down range velocity and energy??

awshucks......Have been selling Excaliburs and a few other brands(including Gold Tip arrows and bolts) longer than I might want to say...Carbon inserts have been around about 15 years, taking weight off the front end stiffens the shaft(mostly for archery applications) The Lazer2 bolt accepts 2117 inserts and if you look around you cay still find a few....I do not like the insert that comes with the Lazer2 bolts(they weigh almost 100g) so I use either the carbon or a regular 2117 insert.....
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Old 06-18-2006, 12:50 PM
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Default RE: How to figure down range velocity and energy??

JQ7: Thanks for the info, I didn't know that. How much do carbon inserts weigh for GT LII's?? With your set-up you described that gets 370 fps outta the Emax can you tell me the total aarow weight?? Thanks for the info, never met somebody I couldn't learn something from.
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Old 06-18-2006, 01:12 PM
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Default RE: How to figure down range velocity and energy??

If any of you are in the area of Heber Springs AR PM me and we will set up a time and get out the chrony. For the info of anyone that might be interested my 10 point[ 185# limbs]gets 312 with out thevibration dampenersand 290 with all the goodies and 2219's with 100gr heads. Lee
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Old 06-18-2006, 01:21 PM
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Giant Nontypical
 
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Default RE: How to figure down range velocity and energy??

And if you look for the there are instructions and balistic calulaters on the internet several on this page
http://home.att.net/%7Esajackson/ke.html
http://home.att.net/%7Esajackson/archery_physics.html
http://home.att.net/%7Esajackson/techinfo.html
Have fun. Lee
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Old 06-18-2006, 01:34 PM
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Nontypical Buck
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Default RE: How to figure down range velocity and energy??

So... if I am shooting 400gr Eastons with a 100gr tip I am shooting a log. Should I drop my arrow weight down a bit with the Pheonix oram I OK? Arrow still seems to be cooking right along. It is nice not having arrows cut to length and just grabbing a handfull and at $5 a pc it is not a bad deal considering I am paying at least a buck a round for rifle ammo and yah can't use them again. The place I get the 400gr Eastons is a10pt dealer so thedraw weight seems alright for the arrow.
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Old 06-18-2006, 02:49 PM
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Default RE: How to figure down range velocity and energy??

Planter: Are you sure about the arrow weight? Seems like 400 w/ a 100 gr tip would be more likely. I'm reading you're at 500 total, which very well can be my error.
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