Keep in mind my experiences knowing that you have 60gr less arrow. Your arrows will slow down faster and not penetrate as far.
Keep away from legs and shoulders and I'd guess to stay under 30yds and you should be fine.
Make that first shot a good one and then you'll have your own data to judge your limits by. It was very easy for me to see how close that 40yd shot came to going through and deciding that more fps would be enough to have me covered.
I don't know why you are being asked how much your arrows weigh when you are already saying how much kinetic energy you have. I know that for Vortex broadheads (they have a 2 1/2" cut) they recommend you have 65ft/lb.
A friend of mine shot completely through a doe at 50 yards with a Vortex and 65 ft/lbs. It was a quartering away shot and he completley severed the shoulder on the exit side.
Because KE has very little to do with penetration, it is only half of the penetration equation.
Many of us have been saying inertia, not KE, is how you judge penetration potential for a long time. Recently a study was finally released that proved us right.
Which do you think will penetrate deeper, a feather going really fast with 50ft/lbs or a comparatively slow 500gr arrow with the same ft/lb?
Inertia is why you can have a light bullet and a heavy bullet both with the same KE but the heavy bullet penetrates deeper (or even the heavy bullet with less KE that goes deeper such as 9mm vs 45ACP).
As for comparing Vortex and Jak-Hammer, you'd have to measure and compare cutting distance, diameter is not everything when judging resistance. Vortex is 2 blade, Jak-Hammer is 3 blade. It's possible that the extra blade on the Jak-Hammer makes up for that extra 3/4".
I wouldn't trust Mechanicals on whitetails, they're only good on elk and grizzlies!!! :wink:
63ft/#'s should be more than enough and if you shoot well enough should do the job all the way out to around 40yds. I wouldn't reccommend shooting any farther than that with any broadhead though. Those Jak-Hammers are devastating, if this is your first time using them, you WILL like them!!!
I used them for 3 yrs. with a set up very similar to yours, a 385gr arrow producing 64 lb of KE. On small does I had no problems with pass thrus. On larger bodied bucks, when shot quartering away and when shooting on a steep angle I had very poor penetration. I always had massive entrance holes, but if they are high, it dont matter still no blood, you need the exit hole to drain blood. I shot a nice buck in kansas at 12 steps, quartering away, the chisel point barely broke the skin on the other side, of course if didnt go very far. I did loose a couple of deer, I had on blood to follow due to a high entrance hole and no exit. I think you need more power to use a 1.75" head. I would opt for the 1.25", thats what I am doing after my experiences with them
I would recommend a 2613 XX78 uncut, filled with sand, 4 eight inch vanes, a 250 grain uranium coated titanium fixed blade head with no less than 3" cut. Fire it from a 175 lb bow at 280 fps. This is what I use for chip munks. It insures that you can break through the steel like shoulder bones of said chip munk and your arrow will pass right through. Normally the arrow can be recovered by sending your address and postage to a resident in China. Oh, you said deer! Scratch my recommendation and just purchase yourself a stinger missle and stay away from the feared indestructable shoulder blade.
Seriously you have more than enough. However, if you listen to some on this site you'd be lead to believe that whitetails require equipment used by the military to kill armored fighting vehicles. If a guy was on the African scene, I could see being more concerned with all the hoopla over KE, inertia, and penetration. Whitetail hunters should look to find a combo that provides a balance between speed and penetration. Then focus on obtaining the skill it takes to put the arrow where it needs to go, in the vitals. Too much focus is placed on this whole bone cracking business and not enough on choosing the right shot and having put in the time it takes to put the arrow in the right place. I have seen complete pass throughs on whitetails with a recurve generating a little over 22lbs of KE. If more hunters places as much emphasis on perfecting their archery skills as they do at obsessing over their equipment, the success rate of the bowhunter would double in the entire world. :beer:
you can say on here that your shooting with 85 lbs of energy and someone will tell you you need a heaver arrow.at what point doesnt it make a difference.to me how well your bows tuned , what type broadhead your using , how far your going to shoot,and your shot placement are the important factors.set up a hunting arrow with the shaft being equal or less than the diameter of the broadhead and your going to get better penetration depending on where you hit.
MYK with all due respect as I am sure you are aware that the formula for KE was developed to know the amount of energy a projectile has due to its weight and speed.
You would be surprised how much a feather can penetrate given the right speed and angle. (After a hurricane there were hay straws inbedded in a wall.)
If he was shooting a 63 ft/lbs of KE and a blunt on the end then yeah he needs more KE.
In order to simplify things we are using KE (specially for whitetail).
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