Total arrow weight
 

Im just curious to see what the choice would be. If you had to pick either a 365 grain arrow shooting 305 fps, or a 450 grain arrow shooting 275 fps.

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I just switched from a 425 gr. arrow shooting 285 to a 365 gr. arrow shooting 310.....;) That's my pick....

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Was that out of the same bow mobowhuntr?

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Yes.

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Good choice in my opinion, KE is comparable but much flatter trajectory with the 365 grain arrow.

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Exactly. There are some negatives to it though.....The bow is a LITTLE louder, not enough to bother me, and there isn't as much momentum, but if I can't blow through a deer w/ that KE, I've got much bigger problems than momentum.

That's why I did it....KE was close to the same, and certainly high enough for what I'm doing, and it flattened me out some.

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If I could get 275 out of a 450 grn arrow I would probably be looking for 500 grn arrow to shoot instead:D;).

I would pick the heavier arrow. I get about 200 fps out of my bow with that weight arrow.

Paul

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I would go heavier too, all about KE and momentum.

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I was shooting a 425gr. arrow 285 fps, holding 76.67 pounds of KE. Now I shoot a 368 gr. 310 fps. holding 78.54 pounds of KE.....AND, I have just a bit more than 1" less drop from 20-30 yards.....Sounds like the lighter arrow wins for me...

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I would rather take a heavier arrow over a lighter arrow. For one your bow will be quieter and the newer bows you are not going to see that big of difference in the amount that your arrow drops anyway. My bow preforms alot better, less noise, less shock on the bow. I have an adjustable one pin sight, but if it is set at 20 yards and i couldn't move it i can easily shoot less than 20 or out to 30 without being more than an inch off on height.

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I dont know what you guys shoot but at 305 grains my bow shoots at 230 fps and it works just fine:eek:

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450 grains is ideal in my opinion. It give you the best combination of everything that matters - speed, accuracy, penetration, and silence. 275 fps is PLENTY fast for hunting.

A 365 grain arrow will be a little faster, but it will be a LOT louder and less accurate with fixed blade broadheads. And you'll lose some penetration if you hit bone.

For 3d shooting I'd take the lighter arrow, but for hunting I'd use the heavier one.

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I was waiting for someone to say something about the heavier arrow having more KE, but both are withing a couple of 10ths of a foot pound. With todays short furrel high quality broadheads the faster arrow will be just as accurate as long as the shooter can do his part. Yes you may gain just a tad more noise and vibration but thats why they make high quality stabilizers and limb savers, string leaches etc. So in the end you have a set up that is shooting flatter, faster and farther and delivering the same amount of energy. Whats not to like about that?

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My choice is the heavier arrow every time to help with momentum. Penetration is dictated by arrow momentum and broadhead design going inversus thestopping force applied by the flesh/bone. Stopping force comes mainly in the form of friction, and friction goes up exponentially with speed (i.e., there is 4x more friction when the speed is doubled across a given surface). My arrows are just shy of 525 grains and fly at 255 fps from my Mathews Switchback at 30" and 69#. I personally make the heavy arrow choice because I hunt mainly elk, and I never know what unforseen problems are lurking that will shave off my penetration ability. The bottom line is shot placement, but when the unseen twig moves my shot placement into the shoulder, then I want to have as much weight as possible to salvage whatever penetration I can.

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YUP, I go heavy.,. but hey, that's just me. I could shoot the 350 grain arrow(But never have) and gain a lot of speed. Instead, I'm shooting the 467 grain arrow at 250. To each his own, but my bow is quieter and easier on the bow with the 467 grain arrow too.[8D]:D

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Ok, I can buy that, but we aren't comparing apples to apples here.....We haven't even come CLOSE to doubling the speed.....Maybe added, what, 20-25%?? So we've really only increased friction by 1x, and from a bow w/ good KE anyway......who cares really??

(disclaimer; I am not arguing, merely stating it as I see it, and trying to learn something in the process.)

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mobowhuntr, I agree that the increase in speed is a small percentage, but it is one of the considerations I take into account in my choice of arrows.I think about these little gains adding up becauseI want every chance I can get at a full pass-through on a quartering elk that I can get.

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Understood, and I suppose I can't really relate as the largest I hunt is deer. It just seems to me, with your heavy arrow and my light arrow producing nearly IDENTICAL KE numbers, it wouldn't be an issue....I'm no physicist though....Hell, I can't even spell it.....

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The KE number is (and I'm trying to say this as quietly as possible in a forum) relatively useless in regards to penetration. It is a directionless number in physics that is a sum of all of the energy imparted into the arrow from the bow. These energies are things like vibration, oscillation, heat, and momentum. The momentum part is the factor that accounts for penetration because it is given a direction vector. KE, however is a good starting point for choosing between two bows that you can shoot well and feel good in your hand; the higher the KE, generally, the higher the momentum that will be imparted into the arrow from the bow, especially when you can tune the bow well to remove oscillations and vibrations from the arrow.

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I was shooting 425 gr. 282 fps, producing KE of 75.06....I now shoot a 368 gr. arrow 310 fps, producing KE of 78.54......So, if higher KE = higher momentum (generally) won't my light arrow be carrying more momentum?? I'm so confused....:eek:

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I thought some more about my last, and I answered my own question......A tractor trailer hits harder than a pick up, even if the pick up were going alot faster.......Momentum, yes?

Ok.....BUT, we aren't talking about 60,000 pound trucks here....we're talking about an arrow w/ a good sharp broadhead on the front of it, and 57 GRAINS of weight difference.....With the flatter trajectory I'm getting now.....I think I'm in a win/win situation....

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MO,
I agree, the numbers sound crazy...that's why I don't like to use KE for much, if anything. The formula for momentum is weight x speed / 225218. According to your numbers, the heavier arrow is producing 0.5322 slug-feet and the lighter arrow is carrying 0.5065 slug-feet. This amounts to 5% less energry for the lighter arrow. When you combine this slightly lowermomentum of the lighter arrow with the fact that the heavier arrow will slow down less quickly over a given distance due to air friction, then the increase in momentum will be more like 8% for the heavier arrow over the lighter one. You are correct, however, that this is merely academic if deer is the largest game you will be hunting. But I'm hoping that I was able to make a complicated idea somewhat easy to follow so you can see why I choose the heavier arrow; that 8% gain may just be the amount that I need to get through a shoulder blade after apoorly placedshot. I practice every day to not need that extra, but I still consciously make the choice to take the best chance I have got to the woods. Good Luck!

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Ok, that's the FIRST time I've seen it explained that way, and the first time I've seen the formula for momentum.....I'm not sure what the heck slug feet are, but I can only guess them to be pretty slimy, much like the slug...[&:]

Actually, thank you a bunch, I understand perfectly now.....I was messin around w/ OnTarget2 last night, and the downrange speed difference of those 2 arrows isn't much, only like 4 fps if I remember correctly....Thanks again, great explanation!

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There is a problem with your numbers.You don't hardly EVER get an increase in ke when going lighter.



Usually there is another problem,like underspined arrows not being as efficient and/ or tune causing a problem.;).Didn't you have problems with this?



friction is idependant of speed once an odject is moving,faster DOES NOT mean more friction.

http://hypertextbook.com/physics/mechanics/friction/ you have to go way down to the bottom right before problems to read this statement.


I actually have a Machinist Handbook that staes that friction decreases as speed increases.Laws of dry friction.



But I would choose the heavier if I could get that kind of speed from a 425 grain arrow,hell,I don't get that from a 365 gr arrow.

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Being from Idaho I too likea heavy arrow for elk. For me a 400 grain arrow is light and I will not dip below that even though the arrowweightlaws changed for this year. We can now use a300 grain arrow,for all big game if weso wish provided we use a fixed blade broadhead.IMO thats way to lightno matter what the circumstances are,heck even a 450 grain arrow like my 7595'sgold tips XT's. Which are mycurrent elk arrows, are on the light side for elk. But on the flip side I sure wish I had a lightweight arrow set up just for antelope out of blinds where the shots can tend to be on the long side.Antelope are smaller than thewhitetails around here and their skin is very thin. Compared to mule deer and elk their bones are easy to slice, breakand penetrate, for most arrow broadhead combo's. Overallit doesn't takea lotKE for a pass throughon them.With that said I am in the process doing this right now for my switchback XT.That bow fully set up isa nice small package thats fitsperfect in blinds. My new Drenalin is comming soon and these last two years I have used the 05 Switchback as my main elk/deer hunting bow. So between them (Drenalin, 05 Switchback)I will have to decide what bow I really like the best for my main hunting bow and what bow will play the back up for this year. That's leaves the XT just sitting waiting to never get used unlessI make itinto aantelope hunting bow. lol Pathetic I know but hey I try hard to play will all the toys in the toy box. lol It might just be a good pay off too come fall!After all I can goantelope hunting knowing that I don't have to play switch a roo with my arrowsat the start of elk/deer season(august 30)which happens to be the middle of the antelope season(august 15 till september 15). In the pastwhen I have archery antelpe hunted I have always justused my elk hunting set up which is awesome under 40 yards. But longer than 40 yards my arrows that drop like rocks. Yes it should be nice, oh wait I just had another idea, maybe my antelope set up will also be a perfect turkey set up. :DWho knows?:Dlol

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KE is good, but its not everything. Momentum is much more important with regards to HUNTING. A heavier arrow will always penetrate better. For 3D and target, a lighter arrow with a flat trajectory is preferable, all you need the arrow to do is stick in the target.

For the smallish whitetails in the south, I don't think it matters much. But if you are going after those big northern/midwestern deer or any big game, I would take a heavier arrow in spades. You aren't giving up much by shooting 275 instead of 305. Your bow will be quieter anyway, and I'd rather have stealth than speed.

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Agreed, and yes, I did. BUT, when I changed to my lighter arrows they were also stiffer so I was able to increase the poundage a little to get it where I like it. The arrows I had before were indeed underspined, so I had to turn the poundage down quite a bit for them to spine properly....These new arrows also seem to transfer energy much more efficiently as well.

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With that kind of energy to be honest it doesn't matter. Both will be overkill for deer and most other animals in the states. I ran both arrows and the numbers are very close for both KE and momentum, and trajectory is fairly close at normal ranges as well.

As far as heavier arrows being quieter or having less shock, well at one time I would say that were true. Or if you were shooting a cheap or old bow. However with the newer bows and stuff we put on them I don't think it matters much. And that really isn't a super light arrow anyway. My bow will shoot arrows that weigh under 300 grns just as shock free and quiet as arrows that weight 500 grns. However I shoot a bowtech Mighty Might VFT that looks like a simms advertisement;). If I did the same thing on my 2000 darton yukon stripped down it would make a difference, but I honestly don't think a huge difference.

I would go with the arrow that spines best and shoots the best out of your set up. In the end that will be the most important thing.

Paul

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So please post this so that others don't get the impression that they can go lighter with arrows without changing anything and increase ke,this doesn't happen hardly ever.;)


The ke increased because the poundage increased.

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Yes, the KE increased because poundage increased, BUT, even before I increased the poundage the KE only dropped by 2 ft. pounds, and from 76 to 74 didn't really matter a hill of beans, especially when I figured in the added benefit of flatter trajectory.

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The difference in trajectory isn't much. We don't care about total drop in these cases but rather where the arrow will hit from where the pin is at.


My bow shoots a 367 gr arrow 257 fps.I can hit the kill zone of a bowhunter deer target(about an 8" kill zone)at 40 yards with my sight set at 35 yards to 43.9 yards.If I were using a slide bar sight and provided I was tuned perfect and made a perfect shot.



My bow shoots a 428 gr arrow 241 fps.I can hit the same target at 40 yards from 35.9 yards to 43.3 yards provided all the above info stays the same.

A loss of less than a yard on both ends.Man that is some trajectory that is needed in a hunting situation.[8D]

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Maybe, but flatter is flatter, no matter how you cut it, and my KE and momentum are still PLENTY good to get the job done....Perhaps it's not the case in every situation.

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Tfox, your speed didnt change much for your arrow weight increase. My old bow was shooting a 365 grain arrow at 310 fps I could hit a 4 inch target aiming dead on out to around 37 yards.My new bow is shooting a 358 grain arrow at 290fps and I cant even hit that 4 inch taget out to 30 yards aiming dead on. My point is regardless of arrow weight that 20 fps makes a big difference in trajectory.

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20 fps out of the same bow at 40 yards with the same poundage is a 1/2" difference on a 3 yard miss(only difference is arrow weight).PERIOD.I have done and proven it too many times.


You are comparing 2 bows with 2 different amounts of stored/potential energies,the differnce is the energy level,NOT the speed.

Theold bow probably has an ibo of around 320 and the new one is probably around 305.That is the difference you are seeing.

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For those that care,here are the downrange statistics at the 2 speeds and weights for my bow.



This chart is for the lighter arrow.Same bow and poundage,just arrows have changed.

Of course,momentum is not shown




This is for the heavier arrow.

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Here is the trajectory of the arrow and weights you asked about.

The lighter/faster arrow
365 gr @ 305 fps





The heavier/slower one.

450 gr @ 275 fps

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I shoot a hunting (whitetails) arrow that weighs in at 462gr.

I don't see me shooting over +/- 30yds, based on the type of hunting I do.

My set-up allows me to take advantage of the heavier arrow without a concern for arrow drop at those yardages. It's why I shoot what I shoot.

Blanket statements, without regard for individual circumstances, are useless (in my opinion). Go with what works for YOUR circumstances.

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I'm shooting 268 fps with a 500 grain arrow. All bets are off when that lighter, faster, higher KE arrow impacts the side of a mountain goat clinging to a cliff with every muscle tensed... Then it's all about arrow mass.

I agree that just for deer I'd go with the lighter set-up though.

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All I hunt is deer, I suppose I might think about increasing arrow weight if I was going after a moose or grizzly. Ive seem my set up blast through too many very big midwestern whitetails to be concerned about penetration. I just prefer a faster lighter arrow. In my opinion it gets to the deer alot faster, so less chance of them jumping the string, it shoots flatter aiding in misjudged distance, and Ive never had problems with penetration. Even on bucks that go 300+ pounds on the hoove.

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For the record,my arrows for whitetail weigh a whopping 380 grains.I also use mechanicals and have no problems penetrating the ground on the other side.However,I am a very good tuner.That is key.[:-]


Oh yea,deer are more likely to jump the string at 15 yards than at 30 yards.:D



I like to debate,can you tell.[8D]


There are alot of misconceptions in the world of hunting/archery nowadays due to marketing.