Trad Gang

The arrow and point combination that I am getting the best flight and grouping with is a little lighter than most often recommended.

Noise is acceptable, just a bit louder than heavier arrows I have tried. Not too noisy to hunt with though. The bow also shoots fine as far as hand shock.

I tried weed whacker line inside the shaft to bring the weight up but the arrows just dont group well.

Should I really be concerned about damaging my bow or penetration on deer?

What kind of bow and what does the boyer say about it?  Some bows are ok at that weight like ILF.

I've shot alot of arrows in that range, out of 50 lbs bows.  Never had a problem shooting through animals.

what kind of arrows.

I suggest 8 gpp  I think most bowyers would agree.

xtrema312

The bow is not ILF,  it is a Bob Lee 1 piece recurve.  

I don't know what Bob and Rob would say about it, I haven't called them or checked their website.

Is 7.6 gpp too light?  As long as it's at least 475 grains, no.  I prefer around 600 grains.  

Then I shoot as heavy a bow as I can with any endurance.

I am finding a 7.6gpp on my 65# longbow is driving arrows like darts. A little noisy though. Still trying to find a good whitetail arrow in this range and will be looking for around 10gpp for hogs this spring. It's an old longbow from Bingham that has four layers of laminate on the limbs. Two wood layers and black fiberglass front and back. Handshock is present with that light weight.

The arrow is GT 3555 with 100 grain point and 3-5 inch feathers and a crest wrap. They weigh in at 410 grains on my scale.

My draw weight is 53.5 lbs at my 29.5" draw length.

My broadheads fly like darts and,  group dead on with field points. I am able to shoot really good groups with this setup and don't want to change it unless I am in danger or blowing a limb.

I believe you will find that Bob Lee will tell you no less than 8gpp if I remember correctly.. However, I would never even consider less that 10gpp for a hunting bow.. but that's just me and YMMV

Quote
My broadheads fly like darts . . .

I don't know anyone who hunts with darts.   :D    Just make sure they hit like arrows.    ;)

Since the bow is a Bob Lee, call Bob Lee Archery. They will have the definitive answer.

You could also thru a weight tube in and see if it flies any different.  I haven't found them to change spine any and you could get  around 90gr with a 3gpi tube, or 140gr with a 5gpi, and 230gr with their heaviest tubes.      I have used the 5gpi in 35/55s for a 560gr arrow and been pretty happy with them.

QuoteOriginally posted by Javi:
I believe you will find that Bob Lee will tell you no less than 8gpp if I remember correctly.. However, I would never even consider less that 10gpp for a hunting bow.. but that's just me and YMMV

+1  :thumbsup:

but hey, shoot whatever ya like, 7gpp, 12gpp, i really don't care, but maybe when it comes to your safety you should care?  :dunno:  

it's interesting that you'd first ask yer question at trad gang rather than going to the source?    :dunno:

Seems that at least every other week, there are threads testinn the waters while exploring the lower limits.

Our equipment, our safety and especially the animals we pursue deserve far more respect.

Need for speed may never escape us and remains the underlying driver. I will accept nothing less in a set-up that pushes well above 'adequate'. Our set-up should always be based on encountering the unexpected and especially one that doesn't require a near perfect shot.

well said, scott.

QuoteOriginally posted by Kenny New:
The arrow and point combination that I am getting the best flight and grouping with is a little lighter than most often recommended.
Should I really be concerned about damaging my bow or penetration on deer?

answer: probably

I think you should be concerned about penetrating deer and bow/personal safety.  Do you have extra shaft length you can cut back an inch or so and add 100 grains tip weight?

Remember...a light weight object may start moving real fast but it will also come to a stop real fast also (think bone hit or angled shots).

Good luck.

i think that in the long run, answers like "maybe" and "probably" are good enuf reasons to go with heavier arrows and change those iffy answers to a positive, irrefutable  "no problem!"

:thumbsup:      Good to have margin.

I just picked up my meat from a whitetail doe I shot last week.  The butcher asked me "what the heck are you shooting?"  I knew I had hit the doe high, but what I thought was a "zing" high in the ribs was a shot that had passed through the spine itself.  I'm the only bowhunter using a recurve and wood arrows in his clientele.  Not a shot I would recommend, but a Stos on the front of a 630 gr arrow (11.2 gpp) went through the side of the spine in a vertebre and then another 4" down into the lung.  I couldn't pull the broadhead in through when dressing the deer so I snapped off the head inside the chest.  Now I know why it was truly stuck!  He had sawed out the vertebre with 4" of d.fir shaft through it and I left it with him to put in his "museum" to show mechanical shooters what a broadhead does.     ;)  

It collapsed, obviously, but because her head was still up I put a second arrow into the chest.  My policy is to keep shooting as long as a shot is offerred and the head is up.

I'm guessing your arrows are full length (or close to it).  I shoot 35/55's out of bows of similar weight; I have a 29" draw and with the arrows cut to 29.5 I can load 250 to 285 on front depending on the bow.

410gr. is too light on a hunting arrow for me.  Cut your arrows a bit (if you can) and you can jack up the point weight.

QuoteOriginally posted by Mr.Magoo:
... 410gr. is too light on a hunting arrow for me.  Cut your arrows a bit (if you can) and you can jack up the point weight.

or, imho, better yet add more up-front weight via a brass insert and/or a heavier steel adapter.  that puts the arrow weight where it will do the most good.

i'm not at all fond of using arrows that are far longer than they need be.  i'd rather find the right shaft spine at my preferred arrow length (29.5") and then work out the arrow's mass weight via point weights.

Shooting lighter weight arrows than the bowyer recommends isn't a good choice. it's really hard on your bow. as you go up in arrow weight more of the bows stored energy goes into the arrow shaft instead of back into the limbs.

often times you'll find you are getting better all around performance in hunting conditions out of your bow with a bit heavier arrow..... I'm not talking just arrow flight or speed....

The one problem I might see would be too light for the stress on bow.

Ultimately, I would go with the bowyer's suggestion regarding arrow weight. Aside from that purpose, grains per pound is completely irrelevant to me. People at times get hung up on that ratio, which is how we end up with discussions about how a 500-grain arrow is lethal out of a 50# bow (10 gpp) but somehow is questionable out of a 60# bow (8 gpp). It defies logic, and yet we hear it all the time.

With respect to your setup, a 410-grain arrow flying well out of a 54# bow is hardly on the lower end for whitetails. If the bowyers says the bow will handle it, I wouldn't give it a second thought.

The 10 gpp so called guideline, in my opinion, for hunting deer sized and smaller game is almost guaranteed to come up in some fashion or referral in these types of threads. There is little to no basis for applying it so general across the wide hunting draw wt ranges. The 10 gpp guide line does have its general application for the bow itself's and the user 's  protection and that too may be design dependent.

Possibly 90% of these quite frequent inquiries for 'Do I have enough?' ,  could be easily resolved  by adopting and establishing a new guideline similar to:  
For deer sized animals:
40............15 gpp..........600 g
45............13 gpp..........585 g
50............11 gpp..........550 g
55#'s.......10gpp...........550 g
60#'s........9+ gpp.........540+
65#'s........+9 gpp..........585+

While this guideline is not near absolute,  the adoption  of a similar guide line would benefit the users, the bow and especially the game we pursue. No need to defend your position, if you choose otherwise since the final arrow wt is in part your personal choice. A new proposed guideline should position us well w/I  an assuring safe zone.

We have the power and right to set a new constructive precedent.

go heavey. 500 plus. dam the speed

I'd check with Bob Lee to see what the warrenty is, if that means anything to you.

You say it shoots good, then it shoots good.  

7.6 gpp is perfectly acceptable.  

I think all the heavy arrow folks are a sub-set of archery.  I've tried to find what their data points are in their experiments to support their theories of heavy arrows, but never get any.

So, if it shoots good for you, then it's good.  

I'd hunt with a 7.6 gpp arrow for sure, if it's well tuned to my bow and quiet.  

Good luck.  And trust your own experiments and judgment.

If its ok with Mr Lee, you are fine hunting deer.

QuoteOriginally posted by Bobaru:
I'd check with Bob Lee to see what the warrenty is, if that means anything to you.

You say it shoots good, then it shoots good.  

7.6 gpp is perfectly acceptable.  

I think all the heavy arrow folks are a sub-set of archery.  I've tried to find what their data points are in their experiments to support their theories of heavy arrows, but never get any.

So, if it shoots good for you, then it's good.  

I'd hunt with a 7.6 gpp arrow for sure, if it's well tuned to my bow and quiet.  

Good luck.  And trust your own experiments and judgment.

That's ok... light arrow folks is another subset altogether..    :bigsmyl:

I'm really glad he brought this up because I checked my arrow weights and had to put in 100 gr. brass inserts, I was way off and that was with a carbon shaft with aluminum footings.

They were great for 3-D and stumping but too light for hunting.

Quote
Should I really be concerned about damaging my bow or penetration on deer? [/QB]

Yes and probably; IMHO

Originally posted by Kenny New:
The arrow and point combination that I am getting the best flight and grouping with is a little lighter than most often recommended.
Should I really be concerned about damaging my bow or penetration on deer?

Chrono your arrows.  From that you can determine the percentage loss of energy by using one arrow versus another arrow. That loss of energy went into the bow.  

My guess is that the loss of energy will be so minimal as to be unimportant, and will not cause your bow to destroy itself.  But, check for yourself.

Out of one of my bows, I've been shooting 7 gpp for years.  I shoot well in excess of 10,000 arrows per year.  The arrows shoot quietly, and the bow is just fine.

By the way, people seem to think that how many years one's been shooting is important the weight of their opinion.  I disagree.  I believe that the weight of one's opinion is whether another can get use of it, or reproduce someone else's results.  But, if years shooting is important, I'm at 46.

Sorry I haven't chimed in here today but, I have been at the hospital all day with my mother.

I appreciate all the response from everyone. Some very good points made.

I think however, that some of you misunderstand my motives. I am not trying to push the limits on purpose with this setup for speed. I have tried a few arrow and point cominations, but just haven't found anything yet that shoots this well.

I am sure I can eventually find another heavier arrow that will shoot well. However, I have only used a few other shaft sizes that I currently have on hand(GT 5575, CE Heritage 250 and Easton 2020).

I am actually not too concerned about penetration on deer. My 16 yr old son uses this same arrow at the same length but with only 25 more grains up front out of a 45 lb Bob Lee takedown. He gets complete pass through penetration on all the deer he has shot. So with a well placed shot I don't think penetration would be an issue after all.

Well if that's the case Kenny, I'd order some brass inserts for the heritage 250's.

That's the same arrow i set up for my 57 pound bow this fall and i love those shafts. i ended up with 575 grains with a 65 grains insert.

Kenny New:  

This is your original post:
(1) " I am getting the best flight and grouping"
and
(2) "Should I really be concerned about damaging my bow or penetration on deer?"

You've already answered penetration - you have correctly found that penetration is fine with that arrow set up.  I wouldn't be surprised.

I wouldn't be worried about damaging the bow.  But, I'm not you.  That's your decision.  I can say that there are a lot of people who worry about damaging a bow at 7.6 gpp.  Ask them where they got their data points.  I'll bet they don't have data points.  They have opinions.  That fine, but opinions are very limited, mine included.  

In my opinion, your bow will shoot just fine with 7.6 gpp arrows.  I've shot plenty of arrow with more and plenty with less weight.

But, if you're concerned, increase your gpp. Anyway, if you're worried about the risk, remember that all life is risky, then you croak.  Hopefully, you don't croak falling out of your treestand, 'cause that's more risky than damaging your bow.

Good luck.

Curious how some folks keep referencing DATA POINTS yet they haven't offered up any themselves..   :bigsmyl:  

My reasoning for shooting an arrow in the ten to twelve grain per pound range is less vibration (which translates into a quieter bow), better flight in windy conditions and more momentum down range; all of these things have been proven by me, to me over a good many years of flinging arrows at both targets and at game.

QuoteOriginally posted by Bobaru:
I'd check with Bob Lee to see what the warrenty is, if that means anything to you.

You say it shoots good, then it shoots good.  

7.6 gpp is perfectly acceptable.  

I think all the heavy arrow folks are a sub-set of archery.  I've tried to find what their data points are in their experiments to support their theories of heavy arrows, but never get any.

So, if it shoots good for you, then it's good.  

I'd hunt with a 7.6 gpp arrow for sure, if it's well tuned to my bow and quiet.  

Good luck.  And trust your own experiments and judgment.

Then you didn't look very far.

Gpp is just a guideline.  I think it becomes less valuable the lighter bow you shoot.  An archer with a 40lb bow cannot afford to givbe away penetration like an archer with a 70lb bow can.

IMHO, 410 grains is very light for anything other than small deer.  Add a weight tube.  You won't lose much in teh way of tuning and you will have a much better performing bow/arrow combination.

jeff Strubberg wrote:  "... An archer with a 40lb bow cannot afford to givbe away penetration like an archer with a 70lb bow can."

You assume there's a correlation between arrow weight and penetration.  I've run a number of tests and cannot find a correlation that has statistical significance.  Have you?

YES

Javi...Not sure I understand what you mean by data points, however changes based on a few data points is a plan for disaster in the statistical world.

Ten - twelve: gpp may translate to less vibration, less noise and more moment - typically should be a given.

I seem to be continuously experimenting both on targets and critters, however never exploited the lower end.

A previous set-up:
51@ 28 350 shaft(6.7 gpi)...100 gn insert...300 grain head 3Bl BH ...611 tot...12 gpp...~32% Ultra-EFOC

1. Completely destroyed two targets($90/ea) in six weeks. The 18 in 1 Rhinehart was warrantied for a year. Note: My previous 18 in 1 lasted ~1 1/2 years with a much less efficient arrow. The other target was a foam layered field point target.

2. Often times required and arrow puller at 3D's.

3. Often times knocked over 3D targets.

4. Have often used 2 fingers to remove 8 gpp arrows, shot from 40 pound bows, from 3D targets. Yes, I realize penetration in soft tissue and targets are quite different, yet I still can't ignore the penetration delta.

5. Backing off 50 grains, thus reducing the FOC has permitted me to continually pound my worn Morrel Outdoor Range for several thousand more rounds. I am still shooting it daily. The worn Outdoor Range target stopped handling the previous arrow set-up in July.


6. Made a frontal shot on a doe and the 1 1/2" BL head exited the inside of the back leg by approx 4 inches. She laid down on the spot.

No longer shoot this set-up:
1. Can't afford the targets
2. Turkey's are my main quarry
3. Believe this set-up would easily qualify for larger game.

The great news is that people still maintain the right to choose their set-up. My concern is that I always hope that it is based on an informed decision and not one data point.

Wasn't me asking for data points,   :goldtooth:    I proved to myself the benefit of increased FOC and mass weight in arrows many years ago..

BTW I hate statistical analysis  :D

Bobaru, look up the Asby testing.  It's available here on Tradgang.  If you haven't seen a correlation between weight and penetration, then you haven't looked AT ALL.  


Take ANY bow, compound, recurve or longbow and start adding weight to the arrow.  As long as you keep the arrow tuned properly, speed will drop and penetration will go up every time.  You can test this yourself if you don't want to accept Dr. Ashby's conclusions.

With enough KE, you can get away with losing some penetration.  When your KE is low to start with, you'd better pay attention to keeping every scrap of it to get through that game animal when things don't go quite right.

Jeff:

Yes.  I have tested.  I've shot several arrows that were tuned to my bow which had different weight.  I ran statistical tests on the results.  I could find no correlation.  Now, that's with arrows that I would consider hunting with and I did the tests for my own use.  

I've read most of Ashby.  He doesn't do statistical tests of significance.  And, he doesn't provide his reader with the data so they may do that.  Therefore, while his work was of interest to me, it was only a starting point.  And, I was not able to reproduce his work.  

When you say "With enough KE, you can get away with losing some penetration."  I would say that, unfortunatly, I have read posts where people have intentionally decreased KE, thanking Ashby, because they believed that they could make up for the loss of energy by increased mass.  

I would say, when all else fails, more KE would be a good thing.  Especially if you're hunting heavy skinned game, or dangerous game.

KE is a crap indicator of penetration.  You really haven't read much on this.  

Take any bow.  I mean ANY bow.  Raise arrow weight.  Shoot it into the same medium as before and you will get more penetration, even though you have lost projectile speed in the process.

KE relies too much on speed and fails to follow increases and decreases in penetration in a linear fashion.

If you can't reproduce Ashby's work, you need to ask why so many other people can reproduce it.  You are doing something wrong.

Jeff:

Perhaps I did test improperly.  That's certainly possible.  But, I thought I did my tests okay.

How did you conduct your tests and what kind of results did you get?

I get the feeling this very closely resembles the Elmer Kieth heavy bullet vs the high velocity explosive expansion arguments. Don't think they will ever agree on that either. My personal feelings are "give me a heavy bullet (arrow) that I can shoot through anything and I'm a happy camper. And no, I can't back up my feelings with fact.

ke aside, imo, the common denominator always has and will be holding weight.  yes, bow efficiency/speed, too.  but mostly holding weight.  there is a big difference 'tween holding 45# and 55#.  

if one ascribed to the 10gpp rule-of-thumb-mantra, that's 450gr versus 550gr.  even if both bows spit out their respective arrow weight, and given the same arrow build save for total mass weight, which would have the edge on penetration?    

take the above scenario to the next level - a 45# reasonably efficient stick bow with a 550gr 12.2gpp arrow.  two issues to contend with - lowered arrow speed and therefore reduced effect killing range (distance).  

then there's arrow design, string design and of course the archer's consistent shooting abilities.

if the 45# bow was of greater than "normal" design/efficiency and capable of a greater than normal arrow speed, well that's a diff'rent story.

Rob, that would be an interesting experiment, since the heavier arrow would maintain its energy longer all other things being equal.. It would also be interesting to see real data on the difference in flat line cast for both weight arrows from the same bow..

"I have read posts where people have intentionally decreased KE, thanking Ashby, because they believed that they could make up for the loss of energy by increased mass."

I have to agree with Jeff.KE isn't the best indicator,I prefer momentum.That's neither here nor there because increasing the arrow's weight,increases both KE and momentum.KE does not go down by adding weight to the arrow.It increases.

Here are some actual figures from one of my bows,51# at 28".I draw about 29":

Arrow weight  Speed      KE     Momentum    

714 grs       155 fps   38.08   .4914

619 grs       165 fps   37.41   .4535

530 grs       155 fps   36.03   .4118

At the time,I was playing around to see how much weight change it took to lose or gain 10 fps.The speed fluctuated a few feet per second so I rounded off those speed figures but they are very close.

I have tested other setups and got the same findings but have never gone above 14GPP.Some say there will be a law of diminishing returns with this,I'm not sure about that except in regards to acceptable trajectory but I plan to find out.

Fred Bear wrote up his impact test results in "Ye Sylvan Archer",in 1943.It's an interesting read.He shot 8 different self bows,45#-68#'s and arrows 300 to 800 grs,in 100 gr increments,so 6 different weight arrows.

In every case,with every bow,impact increased as a heavier arrow was shot.The 45# bow with 800 gr arrow would be at 17.7 GPP.He found that the striking force of a 500 gr arrow from the 61# bow was only 1% more than that of the 45# bow shooting a 600 gr arrow.

Even though his tests told him increasing the arrow weight increased striking force,he chose 10GPP as a happy medium between trajectory and hitting power.And keep in mind,in those days people took longer shots at game than most of us would today.

I've seen basically the same as Jeff and Friend,on the targets and in game.My bag target is highly compacted right now and you can literally hear the difference when the target is hit.

When I test for penetration I use a new,4" thick slab of minicell foam.Regarding the arrow figures for my bow,I also found that when my arrow speed dropped 6% due to added arrow weight,the penetration gain increased 12%.Someone explained to me the physics of that but it's lost from my memory bank.

Anyway,KE actually increases with added arrow weight.If you have access to a chronograph,you can figure that out in minutes.tuffhead.com has a neat little calculator for KE and momentum as well as links to some good articles if you like to read this kind of stuff.

The most important thing is your accuracy. But there is no reason why you can't have accuracy with a heavy arrow.

Accuracy with a light arrow is good
Accuracy with a heavy arrow is better.

Gilbert

I did the math on my arrows after reading the post and came up with an arrow mass that is very light as well 412 grain arrow at 60 lb Montana. It seems to shoot great and is quiet with very little shock.  Is ibo 5 grains for compounds different than traditional equipment?  Sorry for the ignorance but kind of new to the traditional choice.I didn't do this for speed but rather by looking at the manufactures arrow charts. I was between the 5575s and the 7595s.  Looks like I chose the wrong ones.  I do know some science though. Ke =1/2 mv2.  So increases in velocity are squared. Momentum on the r other hand is P=mv.  The argument then becomes which is better ke or momentum.  I can understand both arguments.  We as traditional shooters don't take long shots and therefore momentum wouldn't decrease as much as the arrow won't lose as much velocity down range.  What I do know is that I have read arguments for this on a physics forum and even they can't agree, so fat chance of it being solved here.

QuoteOriginally posted by LBJOE:
...Is ibo 5 grains for compounds different than traditional equipment?  ...

when i checked the ifaa and ibo rules last year there was no mention of arrow mass weight for trad bows.  i doubt there is that today.  i'd love to see how long a typical trad stick bow would last with 5gpp arrows.   :D

Rob - I am not volunteering any of my bows.

I see Fred Bear's name referenced often to the origination of the 10 gpp guideline. I have also vividly recalling the same 1943 artilce in years past. Mr. Bear in fact may be the originator, yet I have never been absolutely convinced.

It was also written that Mr. Bear settled on 10 gpp. Even if he did, what was the specific draw wt's he was using? Possibly, incorrect here, but my recollection was that he was still using heavy draw wts per today's standards even as he got up in age.

My adament opinion remains firmly grounded that by applying a 10 gpp guide line in general remains a suggestive fallacy.

QuoteOriginally posted by LBJOE:
I did the math on my arrows after reading the post and came up with an arrow mass that is very light as well 412 grain arrow at 60 lb Montana. It seems to shoot great and is quiet with very little shock.  Is ibo 5 grains for compounds different than traditional equipment?  Sorry for the ignorance but kind of new to the traditional choice.I didn't do this for speed but rather by looking at the manufactures arrow charts. I was between the 5575s and the 7595s.  Looks like I chose the wrong ones.  I do know some science though. Ke =1/2 mv2.  So increases in velocity are squared. Momentum on the r other hand is P=mv.  The argument then becomes which is better ke or momentum.  I can understand both arguments.  We as traditional shooters don't take long shots and therefore momentum wouldn't decrease as much as the arrow won't lose as much velocity down range.  What I do know is that I have read arguments for this on a physics forum and even they can't agree, so fat chance of it being solved here.

It's not really which is better.  KE is a great measure to compare the efficiency of two bows.  Momentum is a much better predictor of penetration.

PEOPLE!!! if there was 10 block walls 5 feet apart an you had to get thru them..would you use a Volkswagon to go thru or a semi truck????? i want to go all the way out the other side...

I don't know if Fred was the first to embrace 10GPP.He almost always shot 65 lbs.I believe when he hunted the big stuff in Africa,he went up to 75 lbs.

QuoteOriginally posted by sticbow:
PEOPLE!!! if there was 10 block wall 5 feet apart an you had to get thru them..would you use a Volkswagon to go thru or a semi truck????? i want to go all the way out the other side...

Don't throw logic into this discussion.. everyone knows the laws of physics do not apply to archery..   :biglaugh:

QuoteOriginally posted by JimB:
I don't know if Fred was the first to embrace 10GPP.He almost always shot 65 lbs.I believe when he hunted the big stuff in Africa,he went up to 75 lbs.

Here is an excerpt from an article about this very thing... the source is  http://www.bowyersedge.com/arrows.html

Fred, and Howard, Too
In 1943, in an article entitled "Hunting Arrows" published in Ye Sylvan Archer, Fred Bear noted that "the growing popularity of field archery" has "created a demand for light weight, fast arrows." He warned against assuming "that the same qualifications are proper for hunting."
Mr. Bear conducted experiments through a shooting machine with six variously weighted arrows (300-800 grains), each in turn shot through six variously weighted bows (45-68 lbs) to prove his thesis that we should shoot heavy arrows (approximately 10 grains per pound of bow weight) through heavy bows (no less than 60 pounds at full draw for an animal the size of deer). The bows ran a sampling of limb design and materials, some backed, some not, some recurved, some straight, of hickory, yew and osage in various combinations and lengths.
The importance of arrow weight and its impact upon penetration stemmed from his observation that complete pass-through penetration of mortal arrows usually killed humanely and quickly, often near the archer, whereas mortal arrows that stayed within game often caused frightened flight, poor blood trails and, occasionally, even lost game, even when the broadhead exited the opposite side.
Using both a shooting machine and an impact measuring device (a bob, suspended pendulum fashion, that recorded the impact of each arrow with a stylus), Mr. Bear found that on the average "the 400 grain arrow struck 20 per cent harder than the 300 grain, the 500 45 percent, the 600 66 per cent, the 700 82 percent, the 800 100 percent."
He noted also that a 500 grain arrow shot from a 61 pound bow struck with a force within 1 per cent of a 600 grain arrow shot from a 45 pound bow. From the other direction, a 68 pound bow with a 500 grain arrow struck less than 3 percent harder than a 52 pound bow with a 600 grain arrow.
Just as some bows are more stable and forgiving than others, and therefore preferable as hunting weapons, Mr. Bear observed that heavy arrows provide the hunter a margin for error by minimizing mistakes of form likely experienced in less than ideal hunting situations. He observed that heavy arrows, averaging ten grains per pound of draw weight, were "less sensitive to correct loose and form" than lighter arrows, which he labeled comparatively "inaccurate" and "unstable" under hunting conditions.
The implications of all this to the hunting archer? In Hunting the Hard Way, Howard Hill maintained that "all else being equal, penetration is the name of the game." To my mind and preference, this translates to sturdy two blade broadheads at the end of heavy arrows that don't deflect easily from course, shot from quiet, sympathetic bows with the objective being complete pass-through penetration of vital areas on big game animals. If we don't always achieve this objective, it should still shape our equipment choices, as well as determine our shot selection, because our quarry's death is not our only goal.

Javi  
       :bigsmyl:

The bottom line is it is to light for your bow. The safest arrows for a bow are 8gpp and above.

I hate to ask this but why do the arrows say 5575 if that is not the actual weight  of the bows they are to be shot from.  Here is that physics forum post
http://www.physicsforums.com/archive/index.php/t-195119.html

Is 7.6 gpp too light?

From a penetration stand point, perform a search for the applicable polls which address perferred gpp.

The information will likely reveal that 1% may agree and that 99% disagree. This way, you will have reviewed for yourself the the general thoughts from a andequate representative sample.

Friend writes:

"Is 7.6 gpp too light?

From a penetration stand point, perform a search for the applicable polls which address perferred gpp.

The information will likely reveal that 1% may agree and that 99% disagree. This way, you will have reviewed for yourself the the general thoughts from a andequate representative sample."

I saw the poll in question.  I found it interesting.  However, that doesn't answer the question "Is 7.6 gpp too light?"  the poll only answers the question "what weight arrows are people hunting with?"  Even so, the poll can be instructive for new people to guide them on what arrows they may decide to use.  

However, the original question was from a new trad hunter who already had an arrow, 7.6 gpp, and wanted to know if that arrow would damage his bow, or have insufficient penetration.  He already knew that the arrow was the best flying arrow of all he'd made up. And, if I recall correctly, that person came back and said, well, no, penetration wasn't really an issue either - just bow damage.

So, there's been tons of stuff written here that isn't really close to answering his question, all geared toward pointing people to their own personal preferences.  That's normal.  

I would suggest that, if Kenny New likes the way the arrow shoots, likes the way his arrow penetrates, he should keep shooting it because I'm not aware of any evidence that he will damage his bow.  In fact, I've asked on these boards for evidence.  I haven't gotten any.  I mean good evidence that would point to the problem of a 7.6 gpp arrow damaging that bow. There is none!  

I certainly don't want to tell the man how to run his life.  The poll is good for him because it merely says "hey, this is what others are doing."  As far as damage, I think it would be reasonable to say, "some have suggested damage will occur, others aren't so sure, and use your own best judgment becuase there's really no data out there on 7.6 gpp versus bow damage.

And, maybe he can come back with some stories of his successes and failures and lessons learned.  

The only one on here who has posted some "data" is JimB.  Bravo!  Most people have no interest in data, it seems.  I mean, there's nothing wrong with saying "I shoot arrow 'A', and it works for me."  But, that's completely different from "Will arrow 'B' work also?"  or "Will arrow 'B' damage my bow?"

One guy says he hates statistics.  Well, okay.  But, others may be interested in a methodology for discriminating between the effectiveness of different things, arrows in this case.  Statistical analysis is the only, not preferred, but only way to do that.  

Here's what I wonder: since only 1% of archers shoot arrows less than 8 gpp, how is it that so many people know how inferior those arrows are?  I mean, can one really know if one doesn't regularily use them?  

The reason I ask this is because, as I have been writting this stuff, I've noticed that the heavy arrow people have never shown an interest in knowing what results people get with light arrows.  And, when some evidence does get out there, that evidence is discounted, or worse, ridiculed.  That's certainly fine with me.  But, it also doesn't add to the wealth of information on archery that people come to this forum for.

Finally, the write up on this tread about Fred Bear is great.  I really enjoy reading that.  There is nobody deserving more respect in bowhunting than Fred. But, this is 2011 not 1943.  There has been many changes in materials science since then.  And, it occurs to me that in 1943, Fred wasn't stuck in the past, say 1920.

In addition, even though Fred may have had a personal preference, I wonder if he would have been adamantly against the different personal preferences of others, or whether he would have encouraged others and seen how their individual decisions have panned out?  

So, I say to Kenny New, go ahead and shoot your arrows.  Others shoot heavier arrows without problem.  And still others shoot lighter arrows without problems.  I fall in both categories.  And, I have taken large game with arrows lighter than his with no problems.  I've taken game with arrows heavier than his, agian, with no problems.  And, I have yet to damage a bow.  I will tell you if I do.

Good luck.

I would suggest that, if Kenny New likes the way the arrow shoots, likes the way his arrow penetrates, he should keep shooting it because I'm not aware of any evidence that he will damage his bow. In fact, I've asked on these boards for evidence. I haven't gotten any. I mean good evidence that would point to the problem of a 7.6 gpp arrow damaging that bow. There is none!

There is a good reason why the bowyer that builds the bow recommends a 8gpp and above arrow weight to stand behind his warranty.

I'm going to try and give you some facts that will explain why this is. Whether you deem this as "Good evidence" i have no idea.

First of all i base my "facts" on testing bows I've built myself and others I've had here in the shop as well. the easiest way to explain this is watching what happens with your own eyes, but i'll attempt to explain it verbally.

In order to harvest the stored energy in any bow, that energy needs to be transferred to the arrow shaft. You will find a wide margin of bows with different efficiency out there too. to transfer the most energy to the bow, the limb needs to stop dead without flopping around.  the reason you see a higher yield of momentum in a 45 pound bow shooting 600 grains is that the bow has become more efficient because it is transferring a much higher percentage of stored energy to the shaft.

as the draw weight of a bow goes up, and the arrow shaft weight goes down. typically less energy is actually transferred to the shaft. This is where the damage is done that effects longevity of a bow shooting light weight arrows.

The bow still needs to stop the mass weight of the limbs after the arrow leaves the string. With a light weight arrow, the force that goes into the outer limbs and the tips is much higher because it's transfering less energy to the shaft.

in order to build a bow of hunting weight that shoots lighter weight arrows it requires the mass of the outer limb to be reduced, and the correct pre-load to stop the limbs clean is obtained so more energy is transferred to the shaft. the brace height is critical to maintain the tautness of the string, or what bowyer's call pre-load, to make sure that limb is stopping clean.

btw... that noise you hear running a bow at low brace ht. can't be doing the bow any good.

Here lies the problem.... if a bowyer designs a bow and recommends a 7.5 to 8" brace height, and asks that you use no less than 8gpp to be covered under warranty. it means that if you shoot 7.6 grains at a 7" brace, the outer limbs are going to take a beating, and the longevity of the bow will be shortened dramatically. This is especially true of bows  55 pounds and above.


look at the limb tips on these film clips. you can see what happens to these limbs after the shaft has left the string.


there are a bunch of film clips you can look at here. and my intention is not to compare bows... but to show some folks here what's going on in slow motion.....

  (http://i171.photobucket.com/albums/u301/kirkll/HS%20video/th_TDSas-1.jpg) (http://s171.photobucket.com/albums/u301/kirkll/HS%20video/?action=view¤t=TDSas-1.mp4)

Kirk, I hope this gets through to the new archers on the forum... I hate to see new folks get the idea that light arrows do no harm to bows.. it may not happen today or even this year but eventually the damage will add up to limb failure..

This was my intent Javi. They do build target quality bows that are designed for lighter weight arrows, but typically these are lighter draw weight bows under 50 pounds.

I'm a firm believer in the 9-10 gpp for hunting, and dropping back to 8gpi for 3D is good sport when you are shooting longer distances.....

but i too, will not warranty a bow of mine if you choose to shoot lighter shafts at lower brace heights. it's just too darn tough on a bow.

Well guys, I just got off the phone with the folks at Bob Lee Archery. I was told that 7.6 gpp is perfectly acceptable.  The guy I talked to said " at 7.6 gpp your bow is not going to fly apart, I wouldn't be at all concerned " . He also said that his setup is only slightly more at 8.3 gpp.

As far as those who contend that 410 grains is too light for hunting and that you need at least xx weight arrow, I wonder how many that have made less than perfect shots on game and recovered the animal, can prove that a lighter weight arrow would not have been just as effective.

I know from my sons experiences that 435 grains from a 45 lb recurve will effectively take deer so, I am pretty sure I don't have anyting to worry about from a penetration standpoint.

I my compound days, I have made bad shots with heavy arrows and with light arrows. The outcome was the same in both, an unrecovered animal.

Your fine with that arrow....Like everything engineered in the world there are safety factors built-in that far exceed the bows material faiure.. It's not like your anywhere close to dry firing your bow..
Amazing how many experts there are out in the world..

QuoteOriginally posted by Kingstaken:
Your fine with that arrow....Like everything engineered in the world there are safety factors built-in that far exceed the bows material faiure.. It's not like your anywhere close to dry firing your bow..
Amazing how many experts there are out in the world..

Yes it is...  :goldtooth:

Kirk, good post.  

Boeing spends millions of dollars trying to find out failure on oscilling wings, and plan that into their design and maintence cycles.

Unfortunately, I don't think any bowyers have that kind of money to spend finding out the failure rates of their products.  So, like yourself, you simply give it your best guess.  

On my Blacktail, I shoot heavier arrows than my Howett Hunter.  But, truthfully, that's mostly because the heavier arrows shoot better.  And, for me, at the end of the day, if either bow fails, well, ...  it fails.  I'll bet my Hunter will go 100,000 arrows at 7.0 gpp.  I'm about a quarter of the way there.  I'll let you know.  

But, there's a problem.  If it does fail, I won't know for absolutely sure the reason ...  although I'm sure there are "experts" here who would be willing to tell me.

Have a good day, ladies and gentlemen.  It's been fun.

And, Kenny New:  I hope you do well with your set up.  Hunting trad is the best blast I've had that didn't involve jumping out of airplanes.

Truth is a 20lb bow shooting a 100 grain arrow with a field tip on it will kill a deer with the perfect shot.. Don't see many folks in the woods with that set up do you..  :D

No one said your bow was gonna explode in your hands at the next shot, but shooting a light arrow will shorten the life of the bow... the question is how much and how long... and of course do you care..

Can I prove my 12.5 GPP arrow will penetrate better than a 7.6 GPP arrow will... I think so, at least I have to myself and a few hundred students over the years.

Can I prove that my 12.5 GPP arrow is quieter out of a bow than a 7.6 GPP arrow... yep again

Can I prove that my 12.5 GPP arrow is more stable in the wind than a 7.6 GPP arrow... again I reckon so..

The laws of physics really do apply to archery...

Can I make you want to use a 12.5 GPP arrow instead of a 7.6 GPP arrow... evidently not...   :knothead:  

Y'all have a great day... I am and I can prove it..  :goldtooth: