View Full Version : kinetic energy for short draw
July 3rd, 2004, 12:48 PM
I shoot a Mathew LX 72lb. with a 26in draw and a 25 3/4 in. arrow
My hunting arrow weight is 425gn I get 249fps. I here guys that get 80lb of Kinetic Energy. The best I seen to get is about 58lb. I seen to have problems shoot thew on lungs shoots at 30yds. I have used muzzy,thunder head,wasp,rocky mountain, and steel force. I have no problem of killing the deer but it is some times hard to fine them with no blood trail with the arrow still in that blocks the blood from coming out. Does anyone have this problem? Any help.
July 3rd, 2004, 12:58 PM
58lbs is more than enough for elk.....:cool:
Is this broadside shots...quartering away. I blew through a doe with a 2512 out of an older Browning bow maybe putting out 40lb of KE...that was around 20 yards.
At about 12 yards I blew through a pig with some thunderheads and a 60lb Q2. The arrows was stuck in the ground big time.
What arrows are you shooting.....what size broadside...give me the arrow spec's so I can run it through TAP....maybe a possibility that you are underspined but only a possibility...JB
July 3rd, 2004, 03:37 PM
I actually get 2 KE less then your getting at 262fps out of my 70# SQ2 and I have seen arrow blast threw deer out to 47 yards!
That particular hit was an extreme 1/4 away shot.
It was broadside at the shot but turned before my arrow hit her. It entered right in front of her left rear leg, threw the gut, threw the right lung, left the chest, and cut completely threw her front right knee joint, and kept going! I never found the arrow. The deer went not as far... LOL
This was with a 371 grain Beman ICS 400 and a Rocket SideWinder mech head. (100 grain)
Your definately getting more then enough KE is my point.
Beside, your need to check the Momentum numbers over the KE numbers..
Trust me I just went threw all this trying to understand how my 55# recurve blows threw deer too...
The higher your arrow mass the greater the MO. You lose some speed but gain a great deal of wallope!!!
My compound arrows are 371 grains at 262 fps 56 KE and the recurve arrows are 485 grain at 145 fps 25 KE.....
Everytime I raised the weight of the arrow and lowered the speed I still got roughly 25 KE, but saw my MO going up...
Go to www.bowjackson.com and run some of your numbers there. Cool site. You will need your fps though.... Everything else you can calculate there...
July 3rd, 2004, 03:40 PM
BTW my arrows are 26.5" and I have a 27" draw....
Forgot to add that tid bit...
July 3rd, 2004, 05:21 PM
I'm also shooting a lx 70# with a 25inch draw. My arrow weight is about 414 grain and KE is about the same and don't have a problem getting a pass through with a muzzy 3 blade 100 grain broadhead. Bad deal being draw lenght challanged. :mad:
July 3rd, 2004, 08:14 PM
Thats why I shot a Supertec. I have a 27.5" draw. This bow is fast, quiet and forgiving. Very easy bow to shoot. At 65lbs and a 310grain arrow it does 302fps. With my 376 grain ACC 3-49 hunting arrow, it does 270 with 61 ft lbs.
July 3rd, 2004, 10:15 PM
Is your bow tuned properly? It seems you have plenty of energy for a pass through, maybe you are expending too much on an arrow that is sideways. Just a thought.
July 3rd, 2004, 11:29 PM
What Flyguy said .. Check to make sure your broadheads are flying well . Some guys don't notice poor broadhead flight at 20 yards . Get back to 40 or so and watch your arrow in flight to target . A properly tuned bow with 58.53 lbs of kenetic energy should be more than enough . My wife shot through a buck last year with only 42 lbs @ 26'' with 85 gr Thunderhead and blew through him like he wasnt there . Her first deer w/bow !!! I was pumped . I think I got her hooked .
Check your setup really close. Somewhere you are loosing energy . Just cause it shoots through a cronograph fast doesn't mean the energy is being transfered to broadhead on inpact . Make sure your setup is doing all it can to shoot the arrow straight as possable . If you are not sure how to check everything take it to a friend who knows bows well . If not take it to a pro shop to look it over . Good luck ..........Z ;)
July 4th, 2004, 12:58 AM
Man, something is not right. I have only shot one deer (started bowhunting Oct. of last year), but that one deer was shot at 38 yards and the arrows was stuck in the ground. The deer went about 5 yards and fell over--dead--he just didn't know it.
The setup that I had at the time was a parker hunter mag shooting a carbon express terminator hunter with a 145 grain muzzy on board. My weight for the arrow was 487 and the speed was a whopping 218 fps. My KE I believe was about 51.5.
My draw lenth is 26" even. Arrows are at 26 1/4" long.
I would make sure that your arrows are spined correctly for your bow and that they are flying true. What you've described just doesn't sound right.
July 5th, 2004, 06:39 AM
thanks to you all for your info. I have used gold tip 55/75, PSE 300 extreme arrows and bemans and now I have super carbon supreme 55-70 and seen to be doing real good with them. I use 125gn broad heads. I use 4in vanes. When I have the most problem is around 30 yds at big deer that are about 250lb +. Dead side shoots. I have shoot paper with broad heads out to 50yds and getting good bullet holes. I just don"t no what is going on. The last few deer that I harvest were all old deer (5 1/2-7 1/2yrs. Could it be that they are toughter deer or that I am to high in a treestand I hunt some times around 20ft up. I just never herd what is the rigth lbs of Kn. E. before. I just love this A-Talk. Thanks again for all you help.
July 5th, 2004, 01:07 PM
I don't get it either. You should be blowing through deer like they were tissue paper with that set up. As long as you don't hit the shoulder anyway.
July 5th, 2004, 01:16 PM
I agree that there is something going on with your set-up. You should be blazing through even with mechanicals.
As for your KE issues, I am a big fan of huge KE as well. The 26" draw really brings the energy down as you have a much shorter power stroke (compared to a 30" draw).
If you really want more KE, you should consider a higher draw weight bow. I am not saying it is necessary, but it will do the trick. I had 81 ft/pds of KE last year and it was just plain awesome. I blew through deer and my arrow go so far into the dirt that it had to be mailed back from China. ;) ;) ;) Totally unnecessary but fun.
July 5th, 2004, 01:31 PM
Had a client going back o Africa on his 2nd safaris with me Shooting 70# Browning and carbon arrows got 55# of KE
He went back to his 2219s and went up to 70# of KE from same bow he shot a 145 grain Muzzy that killed a huge Eland that went 125 yards and a huge Kudu Bull that did the same both shoulder shot both went down in sight
Both were shoulder hits a doubt the carbon would have done 1/2 half as well
The shoulder of an eland weighs 200#+
Elk are like Kudu but harder to kill Kudu are wimps next to elk.
Heavy arrows give you a lot more Momentum that is what really drive steel home
Penetration is a a story by itself
Pete Shepley shot a Buffalo in Zim witha 96# PSE bow and a light300 grain carbon arrow The arrow went inaboiut 2 inch broke and hug down Pete had to use a rifle to kill it he said eh knew it would happen but he had to try it.
Had Pete shot the buffalo witha 600 or 700 grain carbon he would have had a one shot kill.
You can get carbons now in heavy weights TINK