Speed vs Momentum

[hogdaddy]

i've kept 2 bows for a long time, no first string or bench warmer, just 2 tools for two jobs.

one aprox 400 gr. @ 280ish. fps for all round use and reaching out. lots of FOC, 2 in. feathers, fixed bld.

one aprox 500 gr. w nockternal, blazers, heavy COC bh pretty slow but 30 yds is a long shot around the feeder

kind of like having a .270 and a 45/70

would like more punch but am limited to about 58 lb. which is why i try to make it count.

[enewman]

Oops it post twice

[str8shooter]

enewman - I only posted the chart because you said you couldn't find one in an earlier post. You can calculate momentum on you own - Mass (in grains) x Speed (in FPS) all divided by 225400 (the conversion constant to get to kg x m/sec).

i'm not arguing with anyone on here. We all have to set up our arrows so that we get in our preferred speed range and still have killing ability with the bow setup we have and the distance we are willing to shoot.

We all agree that shot placement is the most important key to accomplishing our task. That's why I practice as much as I do, so I know I can pull the shot off when presented to me.

I think the point of the article however, was that bow manufacturers have pressed the speed issue in order to sell bows, when in fact, Mass has a greater impact on momentum, which is the ability of an arrow to get through an animal and put them down ethically. In addition, we as bowhunters, can do more to modify mass, thereby increasing momentum, that we can change the speed of our bows. Sure we can crank it up to 70 or 80 pounds, but that's not comfortable or even practical in my case. I want a smooth draw with as little movement as possible, so I max out 60 pounds. I can easily change to a heavier arrow and BH to bring the momentum back up so that my arrow does what it's suppose to when it hits flesh.

It's all personal preference and it's all good.

Rock On Brothers and Sisters

[chrischop04]

My arrow weight is 365 speed is 303 for the guy who asked

[rocky]

I don't have a problem with that logic....I've just never picked a speed. I've picked a bow and arrow, and speed just kinda fell into place where it was. I usually hunt around 265-270 fps it seems. Except this year. I'm going a little heavier. Most my shots seem to be within 30 yards and usually within 15.

Most whitetails are killed under 20 yards, I agree, but when hunting the Midwest, shots can be longer.
I've killed three bucks with a combined score of 507 gross, with combined yardage of 17.
But I know the next big deer can be 35 yards, and I want to have a fairly flat arrow.

enewman - I only posted the chart because you said you couldn't find one in an earlier post. You can calculate momentum on you own - Mass (in grains) x Speed (in FPS) all divided by 225400 (the conversion constant to get to kg x m/sec).

i'm not arguing with anyone on here. We all have to set up our arrows so that we get in our preferred speed range and still have killing ability with the bow setup we have and the distance we are willing to shoot.

We all agree that shot placement is the most important key to accomplishing our task. That's why I practice as much as I do, so I know I can pull the shot off when presented to me.

I think the point of the article however, was that bow manufacturers have pressed the speed issue in order to sell bows, when in fact, Mass has a greater impact on momentum, which is the ability of an arrow to get through an animal and put them down ethically. In addition, we as bowhunters, can do more to modify mass, thereby increasing momentum, that we can change the speed of our bows. Sure we can crank it up to 70 or 80 pounds, but that's not comfortable or even practical in my case. I want a smooth draw with as little movement as possible, so I max out 60 pounds. I can easily change to a heavier arrow and BH to bring the momentum back up so that my arrow does what it's suppose to when it hits flesh.

It's all personal preference and it's all good.

Rock On Brothers and Sisters

All comes back to a TRUE IBO rating. A fast IBO bow, produces more K.E. AND momentum.
I prefer a smooth drawing, speedy IBO rated bow.
Now, I can produce good speed, good K.E., and/or good momentum.

[Mudslinger]

Great comments by all that have posted. This thread just goes to show that everyone is right in what they are saying and it is a personal opinion as to what set up you shoot. All have very valid points! Can't argue with what Rocky has done, especially with that monster 8 point he killed. Rocky, I am very jealous and would give anything to have a shot at a trophy like that! Awesome what you have done on those bucks!

[hogdaddy]

never seen a more civilized discussion on such a polarizing topic, we must be growing up

kudos to us. LOL

[chrischop04]

never seen a more civilized discussion on such a polarizing topic, we must be growing up

kudos to us. LOL

Lol we should all feel good about this

[El Coyote]

never seen a more civilized discussion on such a polarizing topic, we must be growing up

kudos to us. LOL

That cause y'all are using big words...

380gr arrow 286fps 65lbs....what should the moment be?

[Mudslinger]

The reason this is so civil is because all the views on the subject are correct. Can't go wrong either way or in the middle!

[haas0311]

So this got me thinking.. I am shooting a KE of 91#. I just calculated my momentum and am at .59. Now according to Dr. Ashby, I should be good for a multitude of game, correct? I am shooting a 430.5 gr arrow at~311fps.

[chrischop04]

There is no right or wrong answer just opinions.

[Javelin]

Most whitetails are killed under 20 yards, I agree, but when hunting the Midwest, shots can be longer.
I've killed three bucks with a combined score of 507 gross, with combined yardage of 17.
But I know the next big deer can be 35 yards, and I want to have a fairly flat arrow.


All comes back to a TRUE IBO rating. A fast IBO bow, produces more K.E. AND momentum.
I prefer a smooth drawing, speedy IBO rated bow.
Now, I can produce good speed, good K.E., and/or good momentum.

This is what I was getting out, you must find the balance you like in flat trajectory and enough umph to push an arrow through a deer which in physics terms is momentum, but if you want to use KE I guess you can, it is just not quite correct in physics terms due to the over emphasis on speed. again think of a 22-250 bullet hitting an concrete wall at 4K fps vs a 44mag 230grain at 900fps. Which is easier to stop? the 22-250 BUT it will probably have more KE

[Skullworks52]

I think this has some to do with this topic...
Good summary by Tim Gillingham
QUSTION:Do I need a heavy arrow for hunting out west?


ANSWER: No not really. More elk and mule deer are harvested every year with a 5575 in their lungs than just about any other arrow size. Weight does not necessarily mean penetration. I would categorize the following things to be most important for penetration.
•Shot placement is number one. You hit the animal in the right place it will go right through. If you hit the opposite rib dead center at 50 yards on an elk, you probably wont blow through even if you are shooting 80 foot pounds of energy and a 430 grain arrow. Set you bow up with a reasonable amount of speed that will help with yardage errors. That will be the biggest factor for great penetration and good shot placement.
•If you are going to change anything from your deer hunting setup to your elk hunting setup, change your broadhead. Use a broadhead that is more sloped and uses a less choppy action of cutting. Although many kill elk with 2” cutting diameter broadheads, being a little more conservative and option for 1 1/8” to 1 3/16” is a little more realistic for reliable penetration.
•Good arrow flight is paramount for good penetration. Loss of energy due to the arrow striking the animal any thing less than perfectly square will result in penetration loss as the energy is not expended directly down the center of the shaft. Make sure you bow is paper tuned very well and your shooting skills up to par.
•Weight consider for me is only a happy medium. I like a 400 grain plus arrow but mainly to help with longer range accuracy and shooting in the wind. I would not shoot my bow below 280 feet per second just to make sure I shoot the magical 400 grain arrow. I would go to a lighter arrow or a faster bow.
ME PERSONALLY: Yes I will say that a heavier arrow penetrates more and a lighter arrow has a flatter traj. but a happy medium is best. Unless shooting elephant with a trad bow

[Skullworks52]

This is what I was getting out, you must find the balance you like in flat trajectory and enough umph to push an arrow through a deer which in physics terms is momentum, but if you want to use KE I guess you can, it is just not quite correct in physics terms due to the over emphasis on speed. again think of a 22-250 bullet hitting an concrete wall at 4K fps vs a 44mag 230grain at 900fps. Which is easier to stop? the 22-250 BUT it will probably have more KE

Ever shoot a plate steel target? try shooting through a 1/4 plate with a .357.. you can with a .22-250. Not arguing just another post.