how heavy is too heavy gpp.

[eric-thor]

well this was inspired to me by my other thread . as to gpp. how much do you shoot i like 9-10gpp . at what point does weight have a negitive effect on ke.does ke. really and acurately define penatration?  

[eric-thor]

im sure someone has the link to enter your data and see what our ke, is and what we can adjust to get the max . if it really matters.

[rastaman]

click here for some techy stuff  

See if this helps.

[dragon rider]

When they achieve the glide angle of a brick, they're too heavy.

[Richie Nell]

http://tradgang.com/noncgi/ultimatebb.php?ubb=get_topic;f=24;t=000002

[WESTBROOK]

When you get tired of shooting under everything.

Eric

[SteveB]

Anything over 10 gpp gives me a trajectory that is unacceptable for me.

[Bjorn]

Another personal preference thing.

[Fletcher]

GPP is a compromise.  I'm pretty comfy in the 10-11 gr/lb range,and have been there for several years.  Over 12 is too much for me.  Just because it works for me, tho, doesn't mean it will be right of you.  My suggestion would be to find the spine perfect arrow flight and experiment out from there with different weight arrows and FOC's.  You don't have to do this all at one time.  Take some time and spread it out and enjoy the journey.  You'll learn a lot in the process.

[GREATBROWNKNOCKEMDOWN]

Iam new to trad archery and am shooting a 47 pound bow at 25inch draw my arrows range from 475 grains to 630 grains and all fly straight the heavier ones drop a lil sooner. so i guess its just a personal choice but wouldnt go under the 10gpp rule!!

[Ragnarok Forge]

Personal chouice.  For clarification on the KE question.  KE means absolutely nothing to penetration.  KE is a measurement of the energy stored in the arrow during flight.  It tells you nothing about how that energy is released into the target.  KE is a number used to sell compound bows.  A well tuned high foc arrow with a razor sharp broadhead at low KE will outpenetrate a similar much lighter, and much higher KE arrow.  Impulse Momentum is what gives you an accurate measure of penetration of an arrow.  Read thru the appropriate Ashby reports for a clear understanding of impulse momentum.

[Friend]

There are are many factors which impact penetratrion. GPP is merely one of the main factors and is not on the top of the list per DR Ashby. The following is some exerts taken from one of Dr Ashby's studies.

ARROW LETHATLITY DEPENDS PRIMARILY ON PENETRATION                                      

PENETRATION ENHANCING FACTORS IN ORDER OF IMPORTANCE(per Dr Ashby)

1.Structural  Integrity- from BH tip and edge strength to nock
                                                  - tiny tip bend results in an average penetration loss of 14%

2. Arrow Flight- the ‘ENABLER’ permits other factors to work at full efficiency
-- Poor arrow flight squanders arrow force
-- Even with every other factor in place, w/o good arrow flight you’ll still have poor arrow performance
-   
3. Extreme FOC ( >19%)   - 1st notable gains are manifested at levels >19%
- Normal FOC - < 12%
- High FOC - >12 % to 19%
- EFOC contributes to a 40% to a 60% increase in penetration having most of the enhancing features
-   
4. Mechanical Advantage - BH MA ranks this high because it has a more pronounced influence on the outcome penetration of a perfectly flying and structurally sound arrow

5. Shaft Dia & ferrule Dia  - 10% penetration gain when shaft dia is 5% smaller than the BH ferrule dia
                                                        - Aver penetration decrease of 30% when shaft dia > BH ferrule dia
                                                        - 40% difference in tissue penetration when comparing a favorable ratio to one w/unfavorable ratio

6. Arrow Mass - Greater mass increases bow efficiency, absorbing more of the bow’s energy when fired.  That means more arrow force.
                                                        - Arrow’s tissue penetration is directly proportional to its momentum

7.    Edge Finish - A smooth, beard shaving sharp honed & stropped edge works best
                                                        - 26% advantage over smoothly filed sharp edge
                                                        - 60% advantage over serrated edges

8. Shaft Profile - Tapered shafts show 8% penetration advantage over parallel shafts and 15% over barrel-tapered shafts
                                                       -  Parallel shafts show 7% advantage over barrel-tapered shafts

9.BH/Arrow Silhouette - Rough & irregular surfaces increase arrow drag in all tissues and is more pronounced during bone penetration

10. Type of Edge Bevel - Single bevel – No down-side to using single bevel BH on any type hit

11. Tip Design - Tips design greatest importance on shots impacting bone. Tonto Tip demonstrates 27.5% better over  2nd best performer(round).

12. Arrow mass(wt) above the heavy bone threshold -  this factor jumps to very near the head of all factors, excepting only structural integrity & perhaps fight arrow quality
                                                                                               -  Bone impacts of one type or another occur on most hits, and bad hits can occur at any time
                                                                                               -  the threshold is at, or very near 650 grains

13.  Arrow force derived from the bow  - substantial gain in arrow force from your bow requires either obtaining a more efficient bow or increasing draw wt            
                                                    - penetration gains obtainable by increasing draw wt pales in comparison to that achieved through better arrow design

[Bowferd]

Thank you, I've read that before but sometimes a short quip is better than a long drawn out sermon.

[eric-thor]

very nice: friend , i like your answer its very involved and seems to be reserched well i asume its from Ashby? some time ago i read his reserch on foc. lol i printed it out and its actually in front of me now though i havent read it in yrs.

[ozy clint]

when i was doing water buffalo arrow development testing with my 69# recurve, i found that i had diminishing momentum figures once i reached 1000gr of arrow mass. after that that point, more arrow mass resulted in the momentum figures going back down. that's 14.5gr/#

[Don Stokes]

I prefer 10-12, and see diminishing performance at 15 and up.

[Terry Green]

Yep...as some have stated...heavier isn't always better.  There is a diminishing return...and also a point of negative return in either too light or too heavy.

[James Wrenn]

When you let go the string and feel a sharp pain in the top of your foot,you probably got carried away with your arrow weight.   :D  

I am only concerned with arrow weight as far as what I feel I need for the animals I hunt.Something in the 400 to 500 range works well no matter what weight bow I shoot them from. If I shot an 80lb bow as long as it was quiet enough I would still shoot no more than 500gns for what I hunt.Any more is just a waste of good trajectory since I am already shooting through everything.jmo

[Cyclone2]

Glad to see the smart A$$ remarks removed by the parrot with no real experience.  An occurrence that is way too frequent these days on chat forums.

Most time 9-11 grains per pound will get the job done all day long, and in some cases you might want to go to 12.  Once you get over 12, you might want to revisit the numbers on momentum to see if you are loosing ground.  Don't worry about KE.  Momentum is were it's at.

Also, if do move from 9 or 10 to 11 or 12, you WILL need to practice burning that new trajectory into your brain or you will shoot under your quarry.

Best of luck to you, and just remember to use common sense.

[RUTANDSTRUT]

i prefer to shoot around 11 (gpp to insure penetration.  trajectory seems to take a big turn over 12 gpp for me