Arrow weight revelation?
09-12-2002, 01:44 PM
#1
Nontypical Buck
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Join Date: Feb 2003
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Posts: 2,994
Arrow weight revelation?
For whatever reason I have been traveling down the road that lighter and faster is better. I wanted the flattest trajectory possible to reduce the potential for misjudged yardage, plus the fact that I prefer a 1 sight pin set up for hunting. I figure an ideal kill zone to be 6", which gives me 3" above and 3" below the line of sight in which to make a killing shot out to 35 yards. I accomplish this with my one pin set at 30 yards. BobCo and others posts in the push come to shove thread made me stop and take a look at things, and here's what I found.
Currently I'm shooting a 332 grain arrow at 318 fps, which is producing a ke of 74. But when it impacts the target 35 yards away, the ke has dropped to 51. Most likely more than adequate with a well placed shot, but who's to say? At midrange my arrow is 3" high, and at 35 yards it's 3" low. A good hunting set up.
Based on the telephone poles BobCo is flinging, I figured for and forumlated to see how my bow should respond at 8 grains per pound , well, really 7.74, after I adjusted the weight to gain back speed lost due to my measly 28" draw weight
. I figured this 542 grain arrow should move along at 276 fps, and produce 92# of ke upon release. 92#! When it hits the target 35 yards away, it's still producing 72# of ke! Quite a bump from the 51# above. So, what was the trajectory loss?
1", up or down. At midrange, I should be 4" high, and at 35 yards 3.9" low. Easily corrected by adjusting my pin from 30 yards to say 25ish, and holding a few inches high on a 35 yard shot, which would be rare anyway.
It's got me thinking, big time. Less wear and tear on my bow, quieter release, gaining a potload of momentum and ke, I can't really see what I'd be giving up, can you?
It doesn't solve my thinking of which type of head to use, but with on target perforance of 72# of ke at 35 yards, should be a moot point, provided the head chosen is quality and reputable.
I see new arrows in my future
Currently I'm shooting a 332 grain arrow at 318 fps, which is producing a ke of 74. But when it impacts the target 35 yards away, the ke has dropped to 51. Most likely more than adequate with a well placed shot, but who's to say? At midrange my arrow is 3" high, and at 35 yards it's 3" low. A good hunting set up.
Based on the telephone poles BobCo is flinging, I figured for and forumlated to see how my bow should respond at 8 grains per pound , well, really 7.74, after I adjusted the weight to gain back speed lost due to my measly 28" draw weight
. I figured this 542 grain arrow should move along at 276 fps, and produce 92# of ke upon release. 92#! When it hits the target 35 yards away, it's still producing 72# of ke! Quite a bump from the 51# above. So, what was the trajectory loss?1", up or down. At midrange, I should be 4" high, and at 35 yards 3.9" low. Easily corrected by adjusting my pin from 30 yards to say 25ish, and holding a few inches high on a 35 yard shot, which would be rare anyway.
It's got me thinking, big time. Less wear and tear on my bow, quieter release, gaining a potload of momentum and ke, I can't really see what I'd be giving up, can you?
It doesn't solve my thinking of which type of head to use, but with on target perforance of 72# of ke at 35 yards, should be a moot point, provided the head chosen is quality and reputable.
I see new arrows in my future
09-12-2002, 01:59 PM
#2
Nontypical Buck
Join Date: Feb 2003
Location: CT, USA
Posts: 3,058
RE: Arrow weight revelation?
Yep..there's a point of diminishing returns on arrow speed..where the extra speed is offset negatively by either KE loss or stability.
My Bowtech BKII, is an exception...Becuase of the way the cam is designed I get better efficiency out of light arrows than I do with heavy..at the most the result are close to even.
Be that as it may, I've tamed mine down from 308 FPS to 280 FPS for hunting purposes. AFAIC for Whitetails any speed over 300 FPS is probably hindering you mroe than helping you. Certainly it COULD provide an advantge in certain circumstances (long field edge shots, western game hunting, etc)...but the advantage would be slim.
In any event I think the optimum speed for a whitetail rig should be in the 260 to 280 range as long as it's controllable and not too noisy. This will help with minor ranging errors, and help calm down an unruly arrow from a case of nerves or excitement.
JeffB
My Bowtech BKII, is an exception...Becuase of the way the cam is designed I get better efficiency out of light arrows than I do with heavy..at the most the result are close to even.
Be that as it may, I've tamed mine down from 308 FPS to 280 FPS for hunting purposes. AFAIC for Whitetails any speed over 300 FPS is probably hindering you mroe than helping you. Certainly it COULD provide an advantge in certain circumstances (long field edge shots, western game hunting, etc)...but the advantage would be slim.
In any event I think the optimum speed for a whitetail rig should be in the 260 to 280 range as long as it's controllable and not too noisy. This will help with minor ranging errors, and help calm down an unruly arrow from a case of nerves or excitement.
JeffB
09-12-2002, 02:08 PM
#3
Nontypical Buck
Join Date: Feb 2003
Location: Memphis TN USA
Posts: 3,445
RE: Arrow weight revelation?
<BLOCKQUOTE id=quote<font size=1 face='Verdana, Arial, Helvetica' id=quote>quote:<hr height=1 noshade id=quote>I figured this 542 grain arrow should move along at 276 fps <hr height=1 noshade id=quote></BLOCKQUOTE id=quote></font id=quote><font face='Verdana, Arial, Helvetica' size=2 id=quote>
You must be pulling at least 90lbs of draw weight. If not there is no bow in the world hitting those kind of speeds at that draw length, including the Black Knight2. Secondly, you can throw all of those estimations out of the window. If you want to see what your bow will do under those conditions, then "TEST" it under those conditions. Don't assume or do calculations shoot it. In archery like life there are limitations to everything. The light but fast thing doesn't mean tweak every little itsy bitsy fps that you can out of a bow(at least not for me) It means stick around 6 grains per pound and significantly improve your arrow trajectory over what you would have been shooting with aluminums that weigh roughly 9.5 grains per pound. Ask anyone that shot aluminum for years and had two pins out to 30 yards and then switched to carbons and only needed 1 pin to 30 yards (witnessed 100 myself) if shooting a lighter arrow won't improve your range estimation errors. Now I can't speak to what an arrow does at 120 yards(never shot one that far and probably won't) but I can tell you exactly what they will do out to 35 yards because I have chronoed aluminums and carbons out to that distance. I would really like to see your setup if you wind up with a setup shooting 276fps with a 542 grain arrow. You would be shooting roughly 150 grains more arrow weight than me at 1.5 inches less draw length(I shoot 70 lbs). WOW
Protect your hunting rights, "Spay or neuter a liberal."
You must be pulling at least 90lbs of draw weight. If not there is no bow in the world hitting those kind of speeds at that draw length, including the Black Knight2. Secondly, you can throw all of those estimations out of the window. If you want to see what your bow will do under those conditions, then "TEST" it under those conditions. Don't assume or do calculations shoot it. In archery like life there are limitations to everything. The light but fast thing doesn't mean tweak every little itsy bitsy fps that you can out of a bow(at least not for me) It means stick around 6 grains per pound and significantly improve your arrow trajectory over what you would have been shooting with aluminums that weigh roughly 9.5 grains per pound. Ask anyone that shot aluminum for years and had two pins out to 30 yards and then switched to carbons and only needed 1 pin to 30 yards (witnessed 100 myself) if shooting a lighter arrow won't improve your range estimation errors. Now I can't speak to what an arrow does at 120 yards(never shot one that far and probably won't) but I can tell you exactly what they will do out to 35 yards because I have chronoed aluminums and carbons out to that distance. I would really like to see your setup if you wind up with a setup shooting 276fps with a 542 grain arrow. You would be shooting roughly 150 grains more arrow weight than me at 1.5 inches less draw length(I shoot 70 lbs). WOW
Protect your hunting rights, "Spay or neuter a liberal."
09-12-2002, 02:09 PM
#4
Giant Nontypical
Join Date: Feb 2003
Posts: 9,175
RE: Arrow weight revelation?
Well, who'da thunk it? <img src=icon_smile_shock.gif border=0 align=middle> <img src=icon_smile_tongue.gif border=0 align=middle> <img src=icon_smile_big.gif border=0 align=middle>
The numbers may or may not be exactly right, but you've got the concept.
Edited by - Arthur P on 09/12/2002 15:12:02
The numbers may or may not be exactly right, but you've got the concept.
Edited by - Arthur P on 09/12/2002 15:12:02
09-12-2002, 02:21 PM
#5
Nontypical Buck
Join Date: Feb 2003
Location: CT, USA
Posts: 3,058
RE: Arrow weight revelation?
Oh my.. I didn't look at all your math...
I believe you need to test shoot it as well...Those numbers seem way off assuming you have a 28" draw and are shooting relatively normal poundage...(60-75 Lbs or so)
I know jumping about 200 grains on arrow weight will AT LEAST effect speed by 40 FPS or so, and probably more...
If your calculations are correct though...I'd like to buy your bow
I believe you need to test shoot it as well...Those numbers seem way off assuming you have a 28" draw and are shooting relatively normal poundage...(60-75 Lbs or so)
I know jumping about 200 grains on arrow weight will AT LEAST effect speed by 40 FPS or so, and probably more...
If your calculations are correct though...I'd like to buy your bow
09-12-2002, 02:31 PM
#6
Join Date: Feb 2003
Location: Miami FL USA
Posts: 208
RE: Arrow weight revelation?
Range and Jeff,
Good info for all!!! My setup is not too different than Range's in that I'm shooting around 307fps with a 350 grain arrow for 73# of KE. I've already pretty tamed the noise problems on my Maverick with limb pocket foam, NV system, limbsavers, and string leaches. I've known for sometime now if I up the arrow weight to around 450 grains it increases the KE to about 84# and only drops the speed to about 20fps to about 285 which is still plenty quick enough. Since my hunting is mostly treestand in hammocks I've elected to leave well enough alone until I go westward to hunt. I haven't had very much trouble with accuracy at all being able to shoot a 5 spot bull out to 40 yds with fixed blades.
I know that Arthur is gloating at this discussion <img src=icon_smile_big.gif border=0 align=middle> He ought to hear what my recurve weights are especially if ash shafts are being shot. LOL!!!!
Aim Hard!
Good info for all!!!
My setup is not too different than Range's in that I'm shooting around 307fps with a 350 grain arrow for 73# of KE. I've already pretty tamed the noise problems on my Maverick with limb pocket foam, NV system, limbsavers, and string leaches. I've known for sometime now if I up the arrow weight to around 450 grains it increases the KE to about 84# and only drops the speed to about 20fps to about 285 which is still plenty quick enough. Since my hunting is mostly treestand in hammocks I've elected to leave well enough alone until I go westward to hunt. I haven't had very much trouble with accuracy at all being able to shoot a 5 spot bull out to 40 yds with fixed blades.I know that Arthur is gloating at this discussion <img src=icon_smile_big.gif border=0 align=middle> He ought to hear what my recurve weights are especially if ash shafts are being shot. LOL!!!!
Aim Hard!
09-12-2002, 02:31 PM
#7
Nontypical Buck
Thread Starter
Join Date: Feb 2003
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RE: Arrow weight revelation?
Ok, here's how I did the math. Tear me apart. And if you'd bother to re-read what I typed the first time, I said I "figured" "forumlated" and "should" a number of times. I realize the actual numbers may or may not bear out in real world testing, which I plan to do at some point in time, but I suspect proportionately they should be close.
318 fps with a 332 grains arrow at 70# (not 350, as I deducted 18 grains to make up for my 2" shorter draw length than the 30" ibo, there's a whole nother thread on why, read it if your skeptical). Now, the 542 grain arrow is 210 grains heavier than the 332 grain arrow. Dividing this by 5 (loss of 1 fps per 5 grains of added weight) gives you 42 fps ESTIMATED lost. 318-42= 276 fps. Did I screw something up?
For what it's worth, I shoot nothing other than a speed nok on my string, and my diamond hornet has the bowtech post feed sabre cam. I have no idea what bow Silentassasin is shooting, but I do know my bow seems faster than most around here, which are primarily hoyt and mathews. When I bought it, I had planned on a Mathews MQ-32, but with the identical set up and arrow, the Mathews chrono'd 50 fps SLOWER. And my bow had 60# limbs on it, a bunch of junk on the string (kisser, peep, two brass nocks, elimnator button, a set of string silencers) and the arrow wasn't IBO. It chrono'd around 275. It's much, much faster now.
318 fps with a 332 grains arrow at 70# (not 350, as I deducted 18 grains to make up for my 2" shorter draw length than the 30" ibo, there's a whole nother thread on why, read it if your skeptical). Now, the 542 grain arrow is 210 grains heavier than the 332 grain arrow. Dividing this by 5 (loss of 1 fps per 5 grains of added weight) gives you 42 fps ESTIMATED lost. 318-42= 276 fps. Did I screw something up?
For what it's worth, I shoot nothing other than a speed nok on my string, and my diamond hornet has the bowtech post feed sabre cam. I have no idea what bow Silentassasin is shooting, but I do know my bow seems faster than most around here, which are primarily hoyt and mathews. When I bought it, I had planned on a Mathews MQ-32, but with the identical set up and arrow, the Mathews chrono'd 50 fps SLOWER. And my bow had 60# limbs on it, a bunch of junk on the string (kisser, peep, two brass nocks, elimnator button, a set of string silencers) and the arrow wasn't IBO. It chrono'd around 275. It's much, much faster now.
09-12-2002, 02:34 PM
#8
Giant Nontypical
Join Date: Feb 2003
Posts: 9,175
RE: Arrow weight revelation?
If the old rule of thumb of 1 fps per every 5 grains of arrow weight is right, then those numbers check out. Of course, there's that other rule of thumb that says 1 fps per every 4 grains. Then we'd be looking at 266 fps and 85 ft lbs of KE. According to my randomly accurate calculations, that is still 79 fpe at 30 yards. But, silentassassin is right. You'd need to fling some logs to find out for sure.
Edited by - Arthur P on 09/12/2002 15:54:44
Edited by - Arthur P on 09/12/2002 15:54:44
09-12-2002, 03:59 PM
#9
Join Date: Feb 2003
Location: Homer LA USA
Posts: 97
RE: Arrow weight revelation?
If we are talking about shooting whitetails does this really matter. With fixed blade broadheads and shooting a relativelty modern bow, then complete pass throughs are almost a certainty with a well placed shot. So I don't see the point in shooting a heavier arrow other than the noise factor.
Now if we are considering mechanicals then you are on the right track.
Here is my take. I get complete pass throughs with carbons, fixed blade heads, at a good old speed of 270. Now I have shot heavy aluminums as well and got complete pass throughs. So why carbons:
1. Durability- I don't know how you guys hunt but I am pretty rough. I am likely to bend an aluminum if I am not careful. Carbon was a good choice.
2.Judging distance. On the 3D course I can judge distance pretty well. Now if I am hunting and a deer comes out, adrenaline takes over and logical judgement drops off like a rock. Now if you are calm as a cucumber when a buck comes out you are either lying or need to be a fighter pilot because "you da man". I am up there shaking like a dog crapping a peach seed. I need all the help I can get.
3. Heck they look cool.
Now, you are right about the noise issue but I don't have a problem with noise. So heavier is not necessarily better. With that said I am not an extreme light arrow man myself. I like the middle. Maybe I should run for office they seem the ride the fence alot too.
Kill a good one this year.
Now if we are considering mechanicals then you are on the right track.
Here is my take. I get complete pass throughs with carbons, fixed blade heads, at a good old speed of 270. Now I have shot heavy aluminums as well and got complete pass throughs. So why carbons:
1. Durability- I don't know how you guys hunt but I am pretty rough. I am likely to bend an aluminum if I am not careful. Carbon was a good choice.
2.Judging distance. On the 3D course I can judge distance pretty well. Now if I am hunting and a deer comes out, adrenaline takes over and logical judgement drops off like a rock. Now if you are calm as a cucumber when a buck comes out you are either lying or need to be a fighter pilot because "you da man". I am up there shaking like a dog crapping a peach seed. I need all the help I can get.
3. Heck they look cool.
Now, you are right about the noise issue but I don't have a problem with noise. So heavier is not necessarily better. With that said I am not an extreme light arrow man myself. I like the middle. Maybe I should run for office they seem the ride the fence alot too.
Kill a good one this year.
09-12-2002, 04:00 PM
#10
Giant Nontypical
Join Date: Feb 2003
Location: Dover, PA USA
Posts: 5,497
RE: Arrow weight revelation?
Rangeball,
There is no "Rule of thumb" anymore for figuring weight/speed estimates......every bow is different and they will not all handle arrow weights similarly.
The only way to check for sure is to shoot different weights thru a chronograph.
You will also notice that a bows KE level doesn't change much from one weight arrow to the other.......
A bow only has one Efficiency level, and KE will only increase SLIGHTLY as arrow weight goes up.
This is real world stuff, and I'll illustrate it for you:
My BowTech "Pro38" Dual Cam is one of the fastest bows on the planet......I have a 30" draw length and am pulling 70# (IBO Specs)
At various arrow weights here's what I get:
350 grain arrow = 333fps = 86ft lbs of KE
370 grain arrow = 323fps = 87ft lbs. of KE
471 grain arrow = 290 fps = 88ft lbs of KE
Here's another illustration:
My Hoyt "Defiant XT2000" Redline 30" and also 70#
w/ same exact arrows.....
350 grain arrow = 308fps = 74ft lbs of KE
370 grain arrow = 299fps = 74ft lbs of KE
471 grain arrow = 268fps = 75ft lbs of KE
You can easily see that the efficiency of these particular bows does not change over different arrow weights.......this will be true of all bows.
If you are getting 74 ft lbs of KE with your set up don't expect much more than that with the heavier arrow.......especially with the shorter power stroke of that comes with a 28" draw length.
This also shows the difference in efficiency and how bows vary shooting different arrow weights........
With the Pro38 Dual Cam I lost 1fps for every 2 grs of arrow weight at the extreme light end of the arrow weight scale (from 350grs to 370grs)........and finally lost 1fps for every 2.35grs over the gap between 350grs and 471grs.
With the Hoyt "Defiant XT2000" Redline I lost 1fps for every 2.22grs at the extreme light end of the arrow weight scale (from 350grs to 370grs)......and finally lost 1fps for every 2.66 grs over the gap between 350grs and 471 grs.
Anyone care to analyze the efficiency between these 2 bows, with respect to arrow weight and the fact that one is a dual cam , and the other a hard single cam??
Anyway Rangeball.......I think you see my point. Making up numbers however logical they may seem doesn'y equal real world shooting and calculating.
Fire those different arrows thru a chrono and break out the calculator. I think you are in for a surprise. <img src=icon_smile_wink.gif border=0 align=middle>
Edited by - Matt / PA on 09/12/2002 21:34:03
There is no "Rule of thumb" anymore for figuring weight/speed estimates......every bow is different and they will not all handle arrow weights similarly.
The only way to check for sure is to shoot different weights thru a chronograph.
You will also notice that a bows KE level doesn't change much from one weight arrow to the other.......
A bow only has one Efficiency level, and KE will only increase SLIGHTLY as arrow weight goes up.
This is real world stuff, and I'll illustrate it for you:
My BowTech "Pro38" Dual Cam is one of the fastest bows on the planet......I have a 30" draw length and am pulling 70# (IBO Specs)
At various arrow weights here's what I get:
350 grain arrow = 333fps = 86ft lbs of KE
370 grain arrow = 323fps = 87ft lbs. of KE
471 grain arrow = 290 fps = 88ft lbs of KE
Here's another illustration:
My Hoyt "Defiant XT2000" Redline 30" and also 70#
w/ same exact arrows.....
350 grain arrow = 308fps = 74ft lbs of KE
370 grain arrow = 299fps = 74ft lbs of KE
471 grain arrow = 268fps = 75ft lbs of KE
You can easily see that the efficiency of these particular bows does not change over different arrow weights.......this will be true of all bows.
If you are getting 74 ft lbs of KE with your set up don't expect much more than that with the heavier arrow.......especially with the shorter power stroke of that comes with a 28" draw length.
This also shows the difference in efficiency and how bows vary shooting different arrow weights........
With the Pro38 Dual Cam I lost 1fps for every 2 grs of arrow weight at the extreme light end of the arrow weight scale (from 350grs to 370grs)........and finally lost 1fps for every 2.35grs over the gap between 350grs and 471grs.
With the Hoyt "Defiant XT2000" Redline I lost 1fps for every 2.22grs at the extreme light end of the arrow weight scale (from 350grs to 370grs)......and finally lost 1fps for every 2.66 grs over the gap between 350grs and 471 grs.
Anyone care to analyze the efficiency between these 2 bows, with respect to arrow weight and the fact that one is a dual cam , and the other a hard single cam??
Anyway Rangeball.......I think you see my point. Making up numbers however logical they may seem doesn'y equal real world shooting and calculating.
Fire those different arrows thru a chrono and break out the calculator. I think you are in for a surprise. <img src=icon_smile_wink.gif border=0 align=middle>
Edited by - Matt / PA on 09/12/2002 21:34:03