rib breaking force

[T-Bone]

I shoot a relatively light bow for elk and moose without any success yet.  I am currently experimenting right now with the heaviest arrows my bow can shoot without unreasonable trajectory, but with perfect arrow flight. I have read all of Dr. Ashbey's reports and with that information, I have been trying to refine my setup.  For those experienced big game hunters out there who understand momentum as pertained to penetration, what is an acceptable level for momentum to consistantly poke easily through ribs on an elk or moose.
Thankyou!!

[Dirty Bill]

Work up to a heavier bow. Shoot heavy arrows with razor sharp broadheads. Elk and Moose are very tough animals.

[T-Bone]

I'd like to work up to a heavier bow, however, for physiological reasons that is not an option.  50 pounds is the max for at least a couple more years.  The only way that I can hunt effectively in the forseeable future is to perfect the arrow I shoot-Hence my question I hope that some can answer without  a side track response or suggestion.

[Bjorn]

T-Bone, do you mean you have shot at and not hit animals yet, or have you hit them with inadequate penetration?
What weight bow are you currently comfortable using?

[Tree man]

It is hard to argue against heavy bows and arrows as insurance but there is so much more to it all. T-bone your interest in good arrow flight is right on target. You are not alone in being limited physiologically to more moderate draw weights and you need not feel disadvantaged. I have heard several FIRSThand reports of good results on Elk with bows drawing in the low 40s. The most awesome bone cutting I have ever witnessed on a deer was with a bow drawing 44lbs @24 inches(A sharp "diamond tipped" Bear Razorhead cut the front legbone completely in two then cut a rib going in and cut  a rib and the edge of the scapula going out.)--- 600grain arrows. I know of 2 Bison killed with a bow drawing 53lbs at 25 inches and another bison with 47 @27.
Follow the route you are on-heavy arrows flying well,sharp 2 blade heads, try to stay off the shoulder and go get 'em.

[T-Bone]

I have shot and killed lots of animals, but only with high poundage bows where lethal penetration was not a concern.  But now I hunt with 50# longbows which is where I have not had any success.  I know 50# can get the job done,  but if I could know what a good target momentum value would be to break ribs, it would help me decide what arrow weight I would like to go with and not sacrifice any more trajectory than I need too.  I realize that a higher poundage would increase my performance, but that is not an option.  I'm a very constant shooter at my 50# bow weight.  All I would like to find out is what momentum works good for punching through ribs as it relates to elk or moose, not deer where 40# and 400 grains punches through ribs easily.

[T-Bone]

Treeman,

Thanks!  I appreciate the advice.  Right now im shooting 610 grains and 2 blade stingers. That gives me around .40 momentum.  I'm curious if that would work good on ribs.

[Dirty Bill]

Do a search on kinetic energy,and that will give an idea of where to start.I've seen Elk killed with a 45# bow,and the arrow passed completely through. It was also a PERFECT shot.

The head was a bear razorhead that I sharpened for a friend that didn't know how to sharpen them. The arrow was aluminum,but I don't remember what # they were.I hope this helps.  

[Gator1]

The real factor in my opinion, aside from
"Draw Weight": Is Arrow Speed and Weight, regardless if it is a 45lb bow or a 55lb bow.

[longbowman]

I've killed a few bull elk and some big black bear with trad. equipment and I wouldn't hunt elk with anything giving me less than .50 on the momentum chart.  I know there are a ton of people that will know somebody who has done it with a twig bow and straw arrow but you owe it to the game to be as leathal as possible just in case of a bad hit.

[T-Bone]

.50 momentum is a 600 grain arrow at 188 fps.  Those numbers are consistant with a 75# longbow.  For me to achieve that from a 50# bow, it would take a 1000 grain arrow.  I don't disagree that .50 would definitely do the job though.
Presumeably for cape buffalo too.

[Bjorn]

T-Bone now I understand where you are coming from; I moved down to 50# last year from 58#, and going back up is just not an option.
I am not a follower of the math, or all that so called 'simple physics' stuff; but if you are getting good flight and you are confident of your shots with 600 grains and 50#, then focus on getting moose and elk to walk in front of your set up-you'll kill them dead!

[Tom Leemans]

This hurts my brain. I'd just shoot the heaviest arrows with the sharpest BH's that fly well out of my bow and not worry about the math.  

[indianalongbowshooter]

Your set-up with 600 gr. arrows is plenty as long as you dont hit heavy bone which goes for 98 percent of bows with big animals like Elk and Moose, dont think ribs will be a problem as long as you have perfect flight.

[Hot Hap]

I'm with Tom. Hap

[Tree man]

T-bone, I think you are good with those 610 grain Stinger tipped arrows. FWIW a couple of years ago I put a Ribtek 125s on the end of a Poplar shaft with total arrow weight of 520 grains through the Scapular ridge on a Javelina. The bow was 45 at 28-I was drawing 27 and arrow speed was about 155fps. Javelina aren't heavy boned but the scapular ridge is heavier than Elk ribs. The head stopped in the off side rib.

[High Tech Redneck]

I believe Dr. Ashby has a report comming out soon with a 50# bow and penetration into water buffalo.  That may answer your question.

[Jason R. Wesbrock]

Crunching the number on my moose setup from 2006, it looks like I had a hair less than .43 lb-sec of momentum. With a 125-grain Ace Standard and proper arrow tuning, I blew completely through my bull, splitting a rib on the exit side.

[Tree man]

Techneck, Pardon my being argumentative but...elk aren't even close to the bone structure of a buff. I think Ashby's testing was with a 54# bow and the arrows were high FOC and over 700grains. Interesting but not really relevant.

[Shawn Leonard]

There is also now prood that you can get away with a lighter arrow and penetrate as well if not better than a heavy arrow by using high FOC, that is why carbon companies are making arrow with built in FOC, it helps with broadhead flight and also the high point weight  will penetrate better than an arrow of the same weight without the high FOC, it has been proven in studies and Dr. Ashby states this as well. Shawn