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#1 TerryfromAR

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Posted 15 September 2011 - 06:27 PM

Alright I need someone to weigh in on this one..... I did the calculations on a website and with my bow shooting 285fps, with a 388gr. arrow, it shows 70ft-lbs of kinetic energy at release. My question is for a complete pass through at 15 yds on a whitetail is 70ft-lbs enough? Also how much will my speed drop by the time the arrow gets to the 15yd mark so I can calculate the KE at 15 yds? My shots are set up for 15 yds or less so that will be the maximum distance I will be shooting.
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#2 Jeremiah

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Posted 15 September 2011 - 09:15 PM

I have software that calculates everything you're looking for. But, the short answer is that you have more than enough there.

The last article I read on the subject still recommended somewhere around 45 ft./lbs.of KE upon impact as a minimum for sufficient performance on white-tailed deer. Your effective accuracy range would likely run out long before you dipped below that mark with your current set-up. (I ran your numbers out to 100 yards on the computer and your KE was still @ 49.18 ft./lbs. with a velocity of 239.05 f.p.s. Of course, there are a lot of specific details of your set-up left out that would tweak things a bit, but that's a basic outlook.)

To answer your other question, 15 yards down range would render a velocity of approximately 277.58 f.p.s., 66.32 ft./lbs. of KE and (bonus) a Momentum of 0.4778.

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#3 Rowdy Yates

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Posted 16 September 2011 - 08:34 AM

The general consensus is that 58 ft-lbs. is enough to harvest large sized game (Elk, Moose, Black Bear, etc.) - 50-65 ft-lbs


Check this web site out if you don't already have it. Jeremiah's calculation software says it all about your setup and you should not have any problems with a sharp broadhead and no other equipment issues like might happen using a mechanical broad head. http://www.backcount.../articles/calc/
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#4 TerryfromAR

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Posted 16 September 2011 - 06:12 PM

Rowdy I shoot mechs. A couple of years ago I got the chance to harvest a 3x3 red stag with my bow thanks to my wife's html website talents, and with a bullseye on a rib I still cracked the adjascent rib even though the first rib was acting like a vise on the arrow shaft. I'm using the same broadheads now as well. The internal bleeding was incredible. He only went about 50 yds after the shot before he crashed and crashed hard. The ribs on this red stag where quite a bit heavier than any I've seen on any whitetail around here. The mechs I shoot actually don't open until they're 3/4 the way in. I've heard about the wedging and deflection of the broadhead itself with some mechs but the design of the broadheads I shoot leads me to believe that this will not be an issue with them.
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#5 TerryfromAR

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Posted 16 September 2011 - 06:17 PM

Jere thanks for the info. I promise it will be put to good use. LOL With that much ke I'm more than good to go.
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#6 Rowdy Yates

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Posted 19 September 2011 - 02:55 PM

Rowdy I shoot mechs. A couple of years ago I got the chance to harvest a 3x3 red stag with my bow thanks to my wife's html website talents, and with a bullseye on a rib I still cracked the adjascent rib even though the first rib was acting like a vise on the arrow shaft. I'm using the same broadheads now as well. The internal bleeding was incredible. He only went about 50 yds after the shot before he crashed and crashed hard. The ribs on this red stag where quite a bit heavier than any I've seen on any whitetail around here. The mechs I shoot actually don't open until they're 3/4 the way in. I've heard about the wedging and deflection of the broadhead itself with some mechs but the design of the broadheads I shoot leads me to believe that this will not be an issue with them.

A red Deer Stag is not much different than a bull Elk when it come to body size and bone size and density. I have read several arguments on using mechanicals on elk and they are some heated discussions both ways. Whitetail deer on the other hand are a smaller animal except in some States where they get pretty darn big and so does Mull deer. My opinion is most mechanicals out of a higher KE bow setup should work fine especially if you can be accurate enough to hit the vital zone. The better solution is to tune your bow so you can shoot a fixed very sharp bladed broadhead. Either way practice so your confidence is high and the rest should come together for you. Good luck Terry.
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#7 TerryfromAR

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Posted 20 September 2011 - 04:59 AM

Rowdy I'm confident enough with the accuracy of my set up that if a good neck shot presents itself I'll take it. I'm driving tacks with this bow out to 30yds. I've been looking at other shot placement points as well. I feel secure in the fact that when the time comes I can make a well aimed ethically lethal shot.
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#8 Rowdy Yates

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Posted 21 September 2011 - 08:00 AM

Rowdy I'm confident enough with the accuracy of my set up that if a good neck shot presents itself I'll take it. I'm driving tacks with this bow out to 30yds. I've been looking at other shot placement points as well. I feel secure in the fact that when the time comes I can make a well aimed ethically lethal shot.



Hey that's impressive-- more bowhunters should take your advice. In my limited ability I myself would stay away from the neck shot because of the odds the neck moves a bunch more than the vitals do generally. Again I'm not a moderator or anything but I'd add a dash of patience in to your hunt and wait for the broadside or quartering away shot and aim for the opposite front leg. And it's just my humble opinion. Again best of luck to you Terry.

Edited by Rowdy Yates, 21 September 2011 - 02:20 PM.

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#9 Leo

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Posted 22 September 2011 - 10:38 AM

I'm gonna add some to this subject. Honestly, looking at Kinetic Energy as the "ONE" thing to predict performance can be extremely misleading and in some cases flat out wrong!

The most important thing to understand about Kinetic Energy is it is, by definition, a form of POTENTIAL ENERGY. Only a portion of potential energy is converted to work energy, unless the efficiency of the energy transfer is 100% (which will not happen!). Work energy is how much force the arrow actually has driving it for it's actual penetration distance. Your broadhead selection can greatly influence the efficiency of this transfer of potential energy to work energy.

It may seem on the surface that this means that since fixed heads do not require energy to open that they will always out penetrate mechanical heads. It is in truth, more complicated than that. Some mechanical heads actually require less energy to penetrate once they are open than some fixed heads. The result is some mechanical heads can out penetrate many kinds of fixed heads. Do not lump mechanical and fixed heads into separate catagories and conclude one is better than the other. There are good and crummy heads in both catagories!

There are many Kinetic Energy Calculators online that help you figure out what your setup should be producing. These calculators that ask for bow type, arrow type, draw weight... only give you a rough estimate. Your actual numbers might be quite different. Actually weighing your arrows and shooting through a chronograph is the only accurate way to get this info.

Is 70ft-lbs enough to get a pass through at 15 yards? For a broadside through the ribs shot, I'd say yes. If you hit vertebrae, that arrow will stop cold! If the broadhead manages to penetrate to the spinal cord, the deer will be dead right there. If the broadhead doesn't penetrate that far, you will have a wounded animal you likely will not recover. The vital area you must hit in the neck with an arrow is very small. Any reaction of the animal at 15 yards will likely cause a miss or wound. You might get away with it once or twice but not every time.
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#10 Rowdy Yates

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Posted 22 September 2011 - 12:47 PM









Dr. Ed Ashby has been trying to answer this question for more than 25 years.
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#11 TerryfromAR

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Posted 28 September 2011 - 09:24 PM

Sorry I haven't been on much, but the puter died and I hate the tablet. I've been getting the last minute stuff prepared for Saturday morning. I've been studying up a bit more as well and my preferred shot is right in the boilerroom, but I am going to take the shot that seems the best with the situation I am presented with. I don't know the angle the deer will come in from or how long they will hang around. I have a small hd camera and a tripod so I'm going to try and video my hunts. I'm also thinking that it will help me with knowing where exactly I hit when it's time to decide how long to wait on the recovery.

Edited by TerryfromAR, 28 September 2011 - 09:25 PM.

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#12 TerryfromAR

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Posted 28 September 2011 - 09:30 PM

Leo as always, your reply is insightful and thourough. Sorry if my spelling is off 10 hr days and insomniac children are killing me lol
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#13 iamyourhuckleberry

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Posted 03 October 2011 - 06:35 PM

Terry,

Some great replies...stick with the higher percentage shots. You won't regret your decision! You can always hunt that deer another day. Wound it and you my never see it again.

We're setting up the big elk camp in 2012...Scooby-Do where are you?
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#14 TerryfromAR

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Posted 05 October 2011 - 08:53 PM

Will, I'll tell ya, this has been a record season so far.... 3 days of hunting, 3 days of seeing deer..... Unfortunately the first day I failed to take into account the difference in my practice arrows with standard vanes, and my hunting arrows with wraps.... which made my 15yd shot placement a bit high, and caused me to shoot right over the back of a doe. I will be using my 10 yd pin from here on out on any shot out to 15 yds..... the 2nd day I hunted I saw a doe that presented a descent shot, but never gave me a chance to draw because she was watching the blind, the 3 day I hunted, I saw 3 together, when I finally got a chance to draw my bow, I tried drawing at an akward angle as to not spook them because THEY were watching the blind as well. The biomechanics worked against me and caused me to strain to draw the bow and make more noise, and they spooked. I am going back tomorrow, and have placed a climbing stand adjacent to the blind, so while they're watching the blind I will be about 12 feet to the right and about 12 feet up. This should allow me to make a good shot without spooking them and put one in the freezer. The buck is apparently nocturnal and only comes out after dark, but that's nothing a doe bleat some doe estrus, and the rut can't cure during gun season.

As far as elk hunting in 2012..... I'll have to see what my finances are doing then. If all works out I should be making more money and have a little bit stuck back by then, So it will probably end up being a roadtrip. My son will be 4 by then, and I have promised him as soon as I get one this year I'll take him with me to "shoot deer" as he puts it. LOL I'm sure he'll want to "shoot elk" too so I may have him in tow...... Just depends on how well he does on the deer hunting this year.. LOL
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