# arrow weight vs. speed/KE



## ctrout (Nov 17, 2010)

I like running numbers on this calculator.

http://www.backcountrybowhunting.com/articles/tools.php

Based on my real world numbers, it seems to be VERY accurate.


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## theroguett (Feb 11, 2006)

I think you should decide how much Kinetic Energy is necessary for the game animal you are going to shoot. I have been told rule of thumb that 50 foot pounds is plent for Deer, & 60 Foot pounds is good for Elk. If you are hunting Bear or Moose, I think much more KE is necessary, however, most of todays modern bows are very efficient and produce exceptional KE even with moderate to light equipment. Example I shoot a Mathews Z7 extreme, I shoot 70 lbs. at 5.43 grains per pound, I use a 100 grain head. I use the calculators on the gold tip web site. you will need to know your total arrow weight including hunting broadhead, which by the way if you get out your scale you will find some heads are close to a practice tip & some are heavier, none the less the other number you need is arrow speed in feet per second, plug this into the calculator & it will give you your KE. My bow produces over 70 Foot pounds of KE which is plenty but I hunt only Deer. Hope this helps


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## Orions_1st (Oct 29, 2010)

The great debate!! My buddies and I have this discussion over and over every year!! It's a very good question, and good concern...honestly, a bow shooting 350fps, with a 455 grain arrow will blast through pretty much anything 'stateside'. Use the calculator to determine your KE, KE is the most important factor in KILLING, although a flatter trajectory is always a plus as well (as i am sure you know) and they do 'comingle' in the world of physics! Like you say, you still have to 'pick a hair and split it'!!! Good luck, and Thank you for your service to this great country!!


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## GeNeRAL_HuNTR87 (May 28, 2008)

thanks for all your help guys!!! im not a big speed freak, but i kno it helps with the miscalculation in yardage(small one like +/- couple yards), im more concerned with a quiet shot, delivering a punch at impact to help insure that beloved pass through and helpin w accuracy, which a heavier arrow helps to an extent, but we all kno accuracy comes from repetition, which isnt a problem, i love shootin, so practice is always happening. i also looked at carbon express' new arrow the "Piledriver Hunter" 11.3 gr/inch...very appealing as well. any one here used these yet, not sure if they're out yet?


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## droppixel (Nov 5, 2010)

Piledriver Hunters - I am sure they are out. Guy at a local shop said they are basically like shooting telephone poles at deer.


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## ClydeWigg3 (Jan 4, 2009)

I shot the regular Piledrivers this year and loved them. Great arrows and tough. Spined my first deer and you could hear the solid wack echo through the woods as it hit his spine like a 2x4. It slid through a doe later this year like a knife through hot butter on an August day. Great arrows and gentle on the pocket too. I think you'd be happy with them. If you aren't sure just pick up a half dozen and try them out. I'm only shooting 60 pounds and have no problem sending one down range.


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## tjl23 (Jan 31, 2011)

I just got my new z7 extreme all set up. I'm at 70# and 29" draw shooting a 445 grain arrow I'm getting 75 foot pounds of KE
The ibo was 330fps. With a 445 grain arrow I'm shooting 275fps. I lost a bit of speed but I'm happy with the KE. Best thing to do is get the speed your bow is shooting your arrows and use the recommended calc from above. Good luck!


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## bcbrave (Feb 14, 2011)

According to the backcountry calculator, I'm shooting 92 foot pounds of KE. My draw length is 30" at 70# and the ibo is 340 and a 420 grain arrow. I dont really no much about KE but that seems really high to me.


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## jim-bo (Feb 10, 2010)

IMO, KE is not the be all end all, neither is speed. There are numerous other factors that one should consider, common sense factors that need to be answered before one applies physics. 
What the heck am I going to shoot, would be one of these questions. Within regular hunting distances (<40m) a 60lb bow is more than sufficient for elk, moose and bears, 70lbs will get there faster and with more energy. 
What kind of broadhead do I intend to use, Cut on Contact, Mechanicals, Chisel points. Different heads will preform differently and utilize KE and momentum differently. A cut on contact will not need KE to deploy blades or to do anything, the momentum of ones arrow propels the arrow into/through the animal, where as a mechanical requires energy to open the blades.
How much can a physically draw, here in Canada it gets pretty cold as will the Northern US, a general rule of thumb here in Alberta is to add 15lbs of draw weight; when your in your stand, blind, hiding behind some bush or behind some god forsaken snow drift and your cold and in an akward position that bow is going to be 15lbs heavier in draw weight. You would think adreneline would take over, but in my experience the adreneline is froze in the lines and your SOL.
How loud is my bow, this may answer your question for you. Some bows are louder than others, and shooting a heavier arrow will help with noise as the string is pushing more resistance and less of the stored energy from the limbs is transferred back into your bow as KE (hand shock & vibration). Or maybe you want your bow to be as quite as possible. 
There are numerous other questions you could ask yourself, like FOC, arrow make/models, alloy v. carbon v. acc. 
Further in my experiences, both light/fast arrows and heavy/slower arrows kill, have pass throughs, hit bullseyes, etc...
However I have found that slower/heavier arrows shoot better in the wind (especially with high FOC's), that gives me more confidence to shoot and to hunt with, the higher amount of momentum also gives me confidence on Canadian moose (smaller that Yukon, bigger than shiras), mule deer, whitetail, and elk. Not that light arrows won't do the job, I just have more confidence with 450 grs moving forward than 350 grs.

So which pill do you want, the red one, or the blue one?


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## bowhuntingnc (Dec 23, 2010)

450 gr arrow on a bow rated for 350fps is a great combo! im shootin an 82nd airborne 30"dl with carbon express piledrivers which are 11.3 gpi.....a little heavier than the fmj. and i love it! just make sure you have a Good target! it will get alot of abuse!


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## slabuda (Aug 21, 2010)

Wow I just used the calculator posted above and it was right on +/- 1 fps. Someone sure did their math on this.


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## arcticbreeze (Jan 2, 2010)

I shoot the CE Piledrivers with 125gr 2 blade broad heads. I hunt big wild pigs and they are tough animals. The area I hunt, you would rarely have a shot over 25 yds.


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## GeNeRAL_HuNTR87 (May 28, 2008)

awesome info guys!! thanks alot again, i ended up purchasing the Bowtech Invasion 29" DL 70#, pretty sure im gonna go with the CE Piledriver Hunters, HHA Optimizer-Lite Ultra DS-XL5510 w/ .10 dia single pin sight, G5 Expert II arrow rest, 7.5" Octane Stabilizer, and the Scott's Archery Silverhorn Release, and of course Rage 2 Blades. Am i forgetting anything? haha thanks again for all the help!!


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