What Is The Downside To Shooting A Heavy Arrow (600gr+) At Deer?

[janesy]

Conversely, I can compare two examples within a year of each other, the difference between the two animals was 50-60 pounds.
- One bear was shot slightly 1/4 away arrow penetrated both ribs and lodged into the shoulder. Arrow weighted 420grn, with a mechanical head and it was traveling at about 340fps at the bow.
- the year prior a slightly smaller bear was hit in the same location, however the arrow was considerably heavier(500+/-), also mechanical, and moving 100fps faster. It also stopped in the same bone, except the bone was shattered.

Great data point right here! 80gr heavier and 100fps faster yet did not go through the bone. Lends credence to the study that says bone penetration comes down purely to arrow weight. Maybe the 650gr threshold is the number. But to be fair putting a mech head through a bone vs. putting something like a 2 blade single bevel through a bone are 2 different things entirely.

Thanks Chris!

I agree Keith regarding the mechanicals. In both of these situations the mech heads were a good comparison, one being a Sweat MOAB, and the other a SWAT X-Mag. Had both if us been shooting a fixed, I suspect the results would have been very different. If Norms lightning bolt had TOTA head on it like it does now, I'm confident the entire arrow would have passed through the bone on the other end.

[grouse]

Has it been proven beyond a doubt that a 600 gr. set up, shot from the same bow with the same broadhead, will penetrate a shoulder bone when a 400 gr. set up will not? It was stated that a heavy arrow doesn't care what tip it has, but can we be sure? Is it not possible that one broadhead performs better at higher speed and another does better with more weight?

I started playing slow pitch softball back in the mid 1970s when aluminum bats were just coming on the scene. There was a 38 oz. max on bats because it was believed that the heavier bats were advantageous because it was slow pitch. Years later, it was decided that bat speed was more important than bat weight. Everyone moved to light bats and the minimum bat weight became important. As far as I know light bats are still the norm.

We don't always know what we think we know. As Duckhunt stated, there is probably a sweet spot in between light and heavy. That sweet spot may be a moving target among various bows with various broadheads. There are a lot of variables.

[Carnivorous]

Go heavy or go home... lol

[janesy]

Has it been proven beyond a doubt that a 600 gr. set up, shot from the same bow with the same broadhead, will penetrate a shoulder bone when a 400 gr. set up will not? It was stated that a heavy arrow doesn't care what tip it has, but can we be sure? Is it not possible that one broadhead performs better at higher speed and another does better with more weight?

I started playing slow pitch softball back in the mid 1970s when aluminum bats were just coming on the scene. There was a 38 oz. max on bats because it was believed that the heavier bats were advantageous because it was slow pitch. Years later, it was decided that bat speed was more important than bat weight. Everyone moved to light bats and the minimum bat weight became important. As far as I know light bats are still the norm.

We don't always know what we think we know. As Duckhunt stated, there is probably a sweet spot in between light and heavy. That sweet spot may be a moving target among various bows with various broadheads. There are a lot of variables.

I think the take away that we lose focus of during these conversations is simply that peoples perspectives, goals, experiences and even opinions change daily. The laws of physics do not.
Has it been proven a 600 grn arrow will always penetrate when a 400 will not? No of course not, that's impossible to prove. But the probability is far greater in favor of the heavy arrow. Anyone who doubts that should spend some time under an apple tree. But that does not under any circumstances make it a better choice for anyone or any given situation, that's the perspective of the shooter.

If weight and penetration were not directly related to each other, they wouldn't make heavier hammers.

[xcaliber]

This is a great conversation and an analogy given here some years back said it would be like a Prius going 40 mph hitting a brick wall VS. a semi truck going 30 mph hitting the same wall. Remember the theory of action & reaction. The heavier load requires more to stop it! All of the physics taken out, I still think 450 grains is the sweet spot, give or take. This is for the common hunter on a budget that buys heavy carbon, puts in the heaviest easily obtainable insert, 110 grains, and uses 125 grain heads, or heavier. You're going to build very good arrows for deer hunting, and perhaps black bear. The large game animals, and dangerous game, you want to hit them with that truck!

[nchunterkw]

Has it been proven beyond a doubt that a 600 gr. set up, shot from the same bow with the same broadhead, will penetrate a shoulder bone when a 400 gr. set up will not? It was stated that a heavy arrow doesn't care what tip it has, but can we be sure? Is it not possible that one broadhead performs better at higher speed and another does better with more weight?

I started playing slow pitch softball back in the mid 1970s when aluminum bats were just coming on the scene. There was a 38 oz. max on bats because it was believed that the heavier bats were advantageous because it was slow pitch. Years later, it was decided that bat speed was more important than bat weight. Everyone moved to light bats and the minimum bat weight became important. As far as I know light bats are still the norm.

We don't always know what we think we know. As Duckhunt stated, there is probably a sweet spot in between light and heavy. That sweet spot may be a moving target among various bows with various broadheads. There are a lot of variables.

Well crap. I typed out a whole response and then it went ...somewhere...

Dr Ed Ashby has done a ton of research on this very subject and has written a bunch of papers that are easy to understand and to me make lots of sense. My point with "the arrow doesn't care", was to try to avoid another broadhead discussion here in this thread. I feel that if you shoot X broadhead on a 400gr arrow and get Y inches of penetration, if you put the same BH on a 600gr arrow you will get "Y plus" inches of penetration. Below is a link to his papers. If you are interested, maybe start with his 12 Arrow Penetration Enhancing Factors paper. It even has an audio file so you can just listen. He has done so much work on this in Africa over the years. His "Bone breaking threshold" of 650 grains came from analyzing something like 196 shots into the rib bones of Asian Buffalo shortly after they were killed so everything was "fresh". And most of those shots came from a 40# recurve. But like with anything, you have to evaluate for yourself. In my mind, all of the concepts he talks about apply directly to crossbow arrows, but maybe we can tweak some things due to the better bow efficiency etc. that we see. But things like perfect arrow flight and 100% arrow and BH structural integrity during the shot apply directly with no doubt. If a BH bends or breaks while going through the animal, your penetration took a major hit. Etc. etc.

https://www.ashbybowhunting.org/ashby-reports

Great discussion Everyone!

[grouse]

This is a great conversation and an analogy given here some years back said it would be like a Prius going 40 mph hitting a brick wall VS. a semi truck going 30 mph hitting the same wall. Remember the theory of action & reaction. The heavier load requires more to stop it! All of the physics taken out, I still think 450 grains is the sweet spot, give or take. This is for the common hunter on a budget that buys heavy carbon, puts in the heaviest easily obtainable insert, 110 grains, and uses 125 grain heads, or heavier. You're going to build very good arrows for deer hunting, and perhaps black bear. The large game animals, and dangerous game, you want to hit them with that truck!

Can a Prius engine propel a semi truck to 30 mph? We're talking about shooting arrows of different weights out of the same bow. If you increase weight of the arrow by the same difference as the weight of the two vehicles you would have an awfully slow arrow. In this case were applying the same amount of energy to two objects that are the exact same size but of different weights. The question, as I see it, is can additional speed compensate for less mass or can additional mass make up for less speed. I don't know the answer, but I suspect it depends on variables

[nchunterkw]

This is a great conversation and an analogy given here some years back said it would be like a Prius going 40 mph hitting a brick wall VS. a semi truck going 30 mph hitting the same wall. Remember the theory of action & reaction. The heavier load requires more to stop it! All of the physics taken out, I still think 450 grains is the sweet spot, give or take. This is for the common hunter on a budget that buys heavy carbon, puts in the heaviest easily obtainable insert, 110 grains, and uses 125 grain heads, or heavier. You're going to build very good arrows for deer hunting, and perhaps black bear. The large game animals, and dangerous game, you want to hit them with that truck!

Can a Prius engine propel a semi truck to 30 mph? We're talking about shooting arrows of different weights out of the same bow. If you increase weight of the arrow by the same difference as the weight of the two vehicles you would have an awfully slow arrow. In this case were applying the same amount of energy to two objects that are the exact same size but of different weights. The question, as I see it, is can additional speed compensate for less mass or can additional mass make up for less speed. I don't know the answer, but I suspect it depends on variables

What you are describing is Momentum. Momentum (P) is mass times velocity or P = mv. In theory 2 arrows could have the same momentum but one be derived more from the mass and one be derived more from the velocity. (so light and fast versus slow and heavy). When an arrow hits something, there are resistance forces that act on it to slow it down. These resistance forces vary with the SQUARE of the velocity. So when you increase the speed say 2X, the resistance forces go up by 4 times....and as an arrow penetrates it is continually shedding velocity so the available momentum at any given point is getting less and less...BUT.....the arrows weight is not changing as it penetrates, so the heavier arrow has higher momentum all the way through. There is more to it, but from this you can see that the arrow that derives it's momentum primarily from the mass will encounter much lower resistance forces, and retain more momentum and thus penetrate further before the resistance forces stop it.

Sorry Dan!! You can't ever take the physics out of it.

Ever watch a TV Deer Hunting show? Lots of those guys are shooting roughly 425gr arrows that are going 300fps. How many do you see stuck in the deer while it runs away?

[AJ01]

What happens when you fire 2 objects that weigh exactly the same at much different speeds?

Say one at 400fps and one at 300 fps?

Who wins?

[janesy]

What happens when you fire 2 objects that weigh exactly the same at much different speeds?

Say one at 400fps and one at 300 fps?

Who wins?

Ok, who has a twin strike? Load up the top limbs with all the rubber and string dampeners you can find, heavy Flemish string, and the works. And the bottom limbs get a factory string and that's it.

[xcaliber]

What happens when you fire 2 objects that weigh exactly the same at much different speeds?

Say one at 400fps and one at 300 fps?

Who wins?

Just like football, the one with the most points wins!

[xcaliber]

This is a great conversation and an analogy given here some years back said it would be like a Prius going 40 mph hitting a brick wall VS. a semi truck going 30 mph hitting the same wall. Remember the theory of action & reaction. The heavier load requires more to stop it! All of the physics taken out, I still think 450 grains is the sweet spot, give or take. This is for the common hunter on a budget that buys heavy carbon, puts in the heaviest easily obtainable insert, 110 grains, and uses 125 grain heads, or heavier. You're going to build very good arrows for deer hunting, and perhaps black bear. The large game animals, and dangerous game, you want to hit them with that truck!

Can a Prius engine propel a semi truck to 30 mph? We're talking about shooting arrows of different weights out of the same bow. If you increase weight of the arrow by the same difference as the weight of the two vehicles you would have an awfully slow arrow. In this case were applying the same amount of energy to two objects that are the exact same size but of different weights. The question, as I see it, is can additional speed compensate for less mass or can additional mass make up for less speed. I don't know the answer, but I suspect it depends on variables

What you are describing is Momentum. Momentum (P) is mass times velocity or P = mv. In theory 2 arrows could have the same momentum but one be derived more from the mass and one be derived more from the velocity. (so light and fast versus slow and heavy). When an arrow hits something, there are resistance forces that act on it to slow it down. These resistance forces vary with the SQUARE of the velocity. So when you increase the speed say 2X, the resistance forces go up by 4 times....and as an arrow penetrates it is continually shedding velocity so the available momentum at any given point is getting less and less...BUT.....the arrows weight is not changing as it penetrates, so the heavier arrow has higher momentum all the way through. There is more to it, but from this you can see that the arrow that derives it's momentum primarily from the mass will encounter much lower resistance forces, and retain more momentum and thus penetrate further before the resistance forces stop it.

Sorry Dan!! You can't ever take the physics out of it.

Ever watch a TV Deer Hunting show? Lots of those guys are shooting roughly 425gr arrows that are going 300fps. How many do you see stuck in the deer while it runs away?

Keith, hunting shows are edited.

[Hatchet]

If you know someone with a Semi to spare I have a Prius waiting for just such a test!

[Hatchet]

Just for the science!!!

[DuckHunt]

I agree that heavier than 350 grains is best. But how much heavier? What is the sweet spot? With the more powerful bows (380+), I think there are far more options to go heavier. With the lower speed bows (335-), you can really see the trajectory arc start to grow as the speed decreases. Sure, scopes and rangefinders can compensate but it certainly complicates vertical shot placement at the outskirts of maximum hunting distances.

Conceptually I understand the trajectory point 100%. But the engineer in me says "let's look at the data" as I'm not convinced it would matter that much. With a multi-reticle scope, you would zero at 20yards, and dial it in to be spot on at 30yards with the 30yd reticle (and 40 and 50 etc). If the deer is 25yards, you split the difference and I feel that is going to be a very accurate shot as both reticles should still be on the deer. SO our max error if you will...would be when the deer is 27.5yards but you think it's 30 or 25 and aim accordingly. (same for 37.5 , or 32.5 yards etc etc.)
Seems like some testing is in order to compare the aiming error between a 400gr arrow and a 600gr arrow.

At 20 yards, and maybe even out to 30, I'm not sure the added weight will affect trajectory enough to make any significant difference at all. From 350gr to well beyond 600, I think it'll only be a matter of how far you want your arrow buried in the ground behind the deer. But when you get in the 40-50 yard range, a five yard ranging error can matter regardless of the arrow weight. It's just that the problem is magnified with a heavier arrow.

For instance, a 350gr 16" arrow travelling 330fps has 15" of drop between 40 and 50 yards. Fired from the same bow, assuming -1fps per every +5 grains, a 600gr arrow would launch at 280fps and would have 21" of drop between 40 and 50 yards. That's 6" of additional drop in a 10 yard window due to the added weight. Granted both arrows have significant arc at that distance and have likely shed a ton of speed. With the heavier arrow, knowing the exact distance of the shot becomes far more important at extended distances. If only all the deer knew they had to stop long enough for us to range them.