10 GPP Rule Justification

[Friend]

10 GPP Rule

I would like a little more history of its origin and its justification. It seems to me that the 10 gpp guideline has been errantly been taken out of context and routinely applied to all draw weights.

Did Fred Bear start this guideline based on the 70# pound bows he shot?-(~700 gn arrow)

KY has no draw wt requirement and a 25# bow with a 250 grain arrow is perfectly legal and meets the 10 gpp guideline. The 10 gpp rule needs to be justified or abolished and more defined applicable standard ranges developed for the game we pursue.

We will always hear a story where certain game was harvested with a minimal set-up.
What about the other archers that failed due to an insufficient set-up? They are out there. Planning for the likely unexpected should be our goal.
The game we pursue comes first and they don’t know about the guideline. They deserve better and we should establish enhanced guidelines before for someone does it for us.

[Eugene Slagle]

I'm not sure of the origins of this rule but one thought is because of the efficiency of a Long Bow or Recurve is better when they are matched with a 10GPP or heavier arrow.

Many if not most compound shooters will go as light as they can get away with including 5GPP which personally I think is nuts.

Virginia has no bow weight regulation in the book just a distance a particular bow arrow combination could be shot to with a broadhead.
125 yards.

[BWD]

Wasn't aware it was a rule. Thought of it more as a guideline, although my bottom line is 500grs. Just don't feel comfortable dropping below that.

[Bonebuster]

I guess it is supposed to be a happy medium, where you are able to absorb as much energy stored in the bow and transfer it to the arrow without loosing too much speed. A good starting point, for sure.

I use it as a rule for all the bows I set up, and have never seen a drawback.

I only own three bows I use alot. One is strictly for fishing, and the other two are a Predator recurve, and a Great Northern Bushbow.

The Predator weighs in at 73 lbs at my draw length, and really likes a "heavy" arrow. The arrows I use for that bow are actually over the 10 GPP rule. The Bushbow seems to prefer arrows at or slightly under 10 gpp.

Performance in terms of speed are very difficult to notice, it is more of how the bow feels when shot. My Predator, for example, produces a "silent" thump on release as soon as you get an arrow in it that is at or above the 10 gpp "rule". A lighter arrow causes it to vibrate just a bit after the arrow is gone. Hard to describe, but easy to feel.

The Bushbow is only 61 lbs at my draw length, and when an arrow is too heavy, it feels "weak".
Get the right arrow. of about 10 gpp, and it comes alive, and feels powerful. Again with the "feely" thing.  :D

[TexasTrad]

I agree that it is a good guideline to help find the right balance between speed and arrow weight.  However, you are right to point out that there is a limit to the draw weights to which it can be applied.  I personally wouldnt want to hunt with a 400 grain arrow out of a 40# bow.  Really, I wouldnt want to hunt with a 400 grain arrow out of a 50# bow, even for Whitetail.  The minimum weight arrow I want to hunt with is 500 or so

[Danny Rowan]

10 gpi is more for the sake of the bow. If you shoot light arrows, the bow is going to take more of the energy from the shot, ie had shock and vibration plus damage to the bow could occur. Most bowyers will state not to use less than 8gpi or you will void the warrenty. Just my two cents.

I shoot heavy arrows out of all of my bows they are 58-64# and I shoot the same arrow out of all of them and I am way over 10gpi and over 800 grains in wt.

[Bonebuster]

For what it`s worth, I have two boys who have been "bowhunters" their entire lives.

They have BOTH taken whitetails with bows drawing 40 lbs and shooting arrows that weighed in at almost exactly 400 grains. The performance from the arrows was excellent.

Using narrow two edge heads, they both experienced arrows making two holes in the hide.
No pass-thru arrows, but a broadhead proudly displayed on the opposite side. Three short recoveries.  

[Spectre]

I like mine about 8gpi for the R&D or the recurve, but 10 or even 12 for the selfbow---it likes 'em heavy.

[Bowwild]

My set-ups are usually 8.8-10.5 GPP. Again, I've been told by the bowyers to keep the weight above 8GPP to save wear and tear on the bow.

I consider my hunting set-up a bit light by many of today's standards.  However, I'm very close to what was normal by recurve shooters when I started in the late 60's and early 70's.

[snag]

sorry....didn't read Danny's post. He said what I was going to say.  

[CRS]

It has been common thought that 8-12 gr/lb is a very good rule.  From my experience it is.

I personally like to aim for 10gr/lb.  I don't get too worried if it a little above or below.

My son has shot two deer with a 40# draw weight and 435gr arrows.  Complete pass throughs.  But they are tuned, skinny carbon, scary sharp two blade broadheads.

On to the minimum arrow weight discussion.  When the state was updating the archery requirements I did an 3 bow study using a homemade shooting machine.

I used three 60# bows.  A longbow, recurve, & compound.  I plotted the arrow weight vs kinetic energy and without exception, every bow showed and increase in efficiency right around the 400gr mark.  This was easily seen by a steepening of the plotted line.  I started at 275gr and went all the way up to a fibergalss fish arrow at 1200gr.  The line continued to increase in slope all the way to 1200gr.  Showing an increased efficiency as the weight increased.  

I tried to persuade the commission to set 400gr  as the sensible minimum, but alas, it was not to be.  Ended up at 275gr because that is where the lightweight arrow technology was at that moment.

I will see If I can find the graphs and post them.

“Did Fred Bear start this guideline based on the 70# pound bows he shot?”

No, but close.  I recall reading that Fred Bear had determined that 9 gpp was what he thought would give optimum flight and penetration characteristics for hunting arrows. I’ve (mostly) followed that rule, and shoot through everything I’ve hunted.

You know what’s funny though?  A guy that will argue that 450 grains is perfect for a 50# bow, but you can’t use 450 grains in a 70# bow.  No kidding…. I’ve seen it.  :^)

[TDHunter]

All good, dido on the 500gr min and work up from there as the weight of the bow go's up.

[SEMO_HUNTER]

I've been down that lost road of "lightening up" and it's a lonesome desolate place to be.      

After I saw the light I began experimenting with my set up and somewhere in the 8.5-11gpp range is what shoots the best out of my recurve. Anything lighter than that causes lots of noise from the bow and honestly isn't nearly as accurate.
My most accurate arrows that I have for my Grizzly are my 512gr. woodies 48# @28" draw. Plus they are super quiet and really thump my 3D buck pretty hard. There's no doubt in my mind that they will Git R Dun!    

[reddogge]

It's not a rule, just a rule of thumb. If you shoot an old classic when you fall under that too much the bow becomes loud and sounds like you are doing damage to it everytime you shoot. It's just an optimum combination of safety, stability, speed, and penetration.

[JimB]

In 1943,Ye Sylvan Archer,Fred Bear wrote an article about his impact testing.He tested arrows from 300- to 800 grains.With every bow,in every case,the more arrow weight,the more arrow impact.Bows from 45# to 68#.I keep hearing Fred advocated 9 GPP.He advocated 10GPP,despite his impact testing that showed the heavier the arrow,the more the impact.He chose a balance between impact and trajectory.In 1943,Fred referenced that few big game were taken over 40 yds(self bows then).With laminated bows,he took much longer shots on game,killing his Bengal tiger at 100 yds,in ,I believe,1963 or 1964.At least,he used a 1963 Kodiak.

Use what makes you happy.Fred based his on 10 GPP for shots out to 40- 100 yds.How far do you shoot?

He chose 10 GP as a balance between impact and trajectory,despite the fact that his testing showed that 17.7 GPP penetrated better.Again,he took shots at game out to 100 yds.Those were different times.Howard Hil went about double that.

[Friend]

As mentioned in my initial post, there will always be vocally heard stories
where trad hunters are taking game with minimal set-ups. This squeaky wheel
, in my opinion, should not be greased. These stories have a distinct tendency to swing the norm unfavorably. Lethality involves many factors and our set-ups should not be based on the lightest arrow weight one can get a way with. Sure light poundage and light arrows can get the job done cleanly when everything is perfect. We are hunting living animals which are normally unpredictable and we don’t have the control to tell the animal to pauses right there while we take a shot. What is warranted is to develop the most efficient and effective set-up possible at our effective hunting ranges and not compromise for what seems best for 3D or other target ranges. We should keep in prospective to enhance lethality, that moderate draw wt increases pale in comparison in what can be gained by improving the over-all arrow design.

Because certain draw wts and arrow wts were the norm of the 60’s and 70’s, doesn’t warrant its continue usage. Few, would consider using the broadheads of that era nor would we see many jumping at the chance to use a Baker climbing stand. We must not take our hunting rights for granted.

Take note of the 2010 Poll results of 526 Trad Gang traditional hunters use.

Choose 1 less then 8 ggp 1% (6)
 
8 - 9 ggp 9% (48)
 
9 - 10 ggp 29% (150)
 
10 - 11 ggp 35% (182)
 
11 - 12 ggp 16% (86)
 
12 - 13 ggp 7% (36)
 
more then 13 ggp 3% (18)

The below minimum GPP targets are what I routinely recommend for setting up both new and veteran traditional archers for deer sized and under game. No, it is no way absolute since there are numerous variables. I am far more comfortable advising trad hunting archers the below minimum recommendations than just applying the 10 gpp guideline for all poundages and game pursued. Note: Been setting up a new traditional archer every month.

#........GPP………Wt
40…..12.5………500
45…..11.0………495
50…..10.0………500
55……9.0…….…495
60……9.0…….…540
65....9.0........585

A newly developed and substantiated minimum GPP guideline for deer sized game, excluding larger and tougher game, would benefit this traditional hunting community. My focus is on the minimum since that as humans, we have the propensity to target the minimum.

Bare minimums for other game would be beneficial.


Let’s stay in the driver seat.

[joe skipp]

When I carried 7 lines of custom bows here in my shop, every bowyer was adamant they would not warranty a bows limbs if the shooter used less than 8 gpp. All about energy transfer...

I always recommended the 8-10 gpp for optimum performance. I believed that anything over 10 gpp was overkill even though certain bows handled the extra weight well.

To each his own, shoot what you feel comfortable with but I would not go under 8 gpp. Just my 2 cents...

[flyfish1]

If you ever watch any bowhunting shows you will quickly notice how many times they can not shoot thru whitetail deer with the " latest greatest" equipment. That tells me alot!

[Rob DiStefano]

in terms of detrimental "shock" value to you and yer bow, both will know if the arrow used is too light.  

in terms of penetration at prescribed distances, you will only know that from reasonable testing.

it's a compromise of efficiency (penetration and shock) and trajectory (speed).

i won't go lower than 9gpp.  no matter what the arrow weight, if too much energy is dissipated to the limbs and riser (and bow hand/arm), i'll go higher in mass weight 'til it all smooths out.  
     
if ALL my shots were 15 yards and under, i'd be using mega gpp arrow weights.