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View Full Version : Poundage vs speed question - Defender



azone5
March 11th, 2005, 11:03 PM
I'm shooting a BowTech Defender I got about two weeks ago. At 59#, my 293 gr Lightspeeds were faster than my 280 gr ones. However, at 61# the 280s are faster. This raises several questions. First, this could be a chrono problem. Second, is the bows performance just better at 59# than 61#?

Any ideas?

Thanks.

Mickey

WindWalker
March 12th, 2005, 12:31 AM
Is the Bowtech Defender designed/warrantied to shoot shafts that are less than 5 grn per Lb. of draw-weight? :confused:

azone5
March 12th, 2005, 11:13 AM
What an intelligent, intuitive response. Thanks!

WindWalker
March 12th, 2005, 05:50 PM
??

Dave Nowlin
March 12th, 2005, 06:05 PM
You can slam me if it makes you feel better but I have to agree with windwalker. The answer is no. I also have a 60# Defender and it shoots very well with a 425 grain arrow. These are truly hunting bows and as such I believe you will find they are quieter and perform better at 6 grains per pound or heavier. You are of course free to do whatever you choose, but out of respect for the big deer of Illinois I will shoot a heavier arrow. Our outfitter in Pike County this year had a lot of deer that weren't recovered and believes the problem to be folks shooting light arrows and getting marginal hits. :)
Dave Nowlin

babykeit
March 12th, 2005, 06:13 PM
You can slam me if it makes you feel better but I have to agree with windwalker. The answer is no. I also have a 60# Defender and it shoots very well with a 425 grain arrow. These are truly hunting bows and as such I believe you will find they are quieter and perform better at 6 grains per pound or heavier. You are of course free to do whatever you choose, but out of respect for the big deer of Illinois I will shoot a heavier arrow. Our outfitter in Pike County this year had a lot of deer that weren't recovered and believes the problem to be folks shooting light arrows and getting marginal hits. :)
Dave Nowlin
You may want to go to a lighter arrow . With that set up I think you can get better KE with a lighter arrow. Better for the big boys

Top Cat
March 12th, 2005, 06:13 PM
You can slam me if it makes you feel better but I have to agree with windwalker. The answer is no. I also have a 60# Defender and it shoots very well with a 425 grain arrow. These are truly hunting bows and as such I believe you will find they are quieter and perform better at 6 grains per pound or heavier. You are of course free to do whatever you choose, but out of respect for the big deer of Illinois I will shoot a heavier arrow. Our outfitter in Pike County this year had a lot of deer that weren't recovered and believes the problem to be folks shooting light arrows and getting marginal hits. :)
Dave Nowlin

Not slamin' but I think the key words in your post are "marginal hits"

Dave Nowlin
March 12th, 2005, 06:19 PM
Yes some of these guys hit the shoulder, however a friend of mine took a 275# Canadian Buck this past season with a complete pass through on both shoulders using a 100 grain Slick Trick. He didn't plan it that way the deer was moving through a very narrow shooting lane. He just took the shot he had. :)
Dave Nowlin

azone5
March 12th, 2005, 11:02 PM
I didn't say a word about hunting in my original post because my question didn't have anything to do with that topic. My question, maybe worded poorly, was about bow performance. Can a bow shoot a heavier arrow faster at a lower draw weight, i.e. 59# rather than 61#? And if so, why?

Everyone knows the 5 gr/lb rule...but that's at a 30' draw. I'm a 26" draw.

WindWalker
March 13th, 2005, 02:52 AM
azone5:

Pardon the hell out of everyone that was unable to read your mind!

Your initial post lacked the essential details necessary to enable someone to intelligently and adequately answer your question(s). The question(s) you asked were too generic and stemmed from a personal event involving only your physical specs, your shooting form, your bow, your setup, your chrono, etc, and do not (questions) have a conclusive answer that can be universally applied.

You did not articulate that your (bow/arrow) performance related questions did not apply to a hunting setup. However, what does that have to do with the price of tea in accordance with the questions you asked? Additionally, you did not say what your draw-length was.

Considering that your questions were not properly supported with the necessary data that an experienced archer would have intuitively provided, I, maybe mistakenly so, assumed you are not yet sufficiently proficient in the tuning skills. Therefore, I thought it best that it first be determined that you were not shooting shafts that were too light in spine for the bow’s tolerances.

Ignorance is excusable; arrogance is not.

PS: Everyone does NOT know about the X-grn x lb. rule; or what the consequences can be if he or she violates the "rule."

Big Country
March 13th, 2005, 05:21 AM
Only two possible scenarios I can think of here.....

1. Chronograph is not always reading correctly.

2. Spine of arrows used are marginal at best.

I would bet on the chronograph being wrong. While spine can certainly be a big factor in performance, the fact that you only noted changing draw weight by 2 lbs. leads me to the chronograph. :)

Big Country
March 13th, 2005, 05:27 AM
You may want to go to a lighter arrow . With that set up I think you can get better KE with a lighter arrow. Better for the big boys


Unless you are dealing with an arrow that is spined completely wrong for your setup......a lighter arrow, while not losing any significant KE, will surely not buy you any more. I am not against moderately light arrows, just pointing out a tried and true fact.

Actually, if you use an two arrows that are both properly spined for one specific bow setup, one arrow very heavy, the other arrow very light....the KE will be very close.

Any given bow setup is only capable of "X" amount of KE, regardless of what you are shooting out of it.

After lots of testing on this subject, I don`t recall ever seeing a really heavy arrow ever gaining more than 4 ft/lbs of KE over a much lighter arrow.

azone5
March 13th, 2005, 12:03 PM
Thanks for the replies. The arrows are properly spined. I have an excellent pro shop nearby and use SFA to check specs, too. I'll try a different chrono.

Jerry/NJ
March 13th, 2005, 12:45 PM
Can a bow shoot a heavier arrow faster at a lower draw weight, i.e. 59# rather than 61#? And if so, why?


If the same arrow is used at both settings, the answer is no.
A bow (in most cases) will be more effecient with a heavier arrow.

azone5
March 13th, 2005, 03:14 PM
It's the same arrow. The only difference is one has feathers, the other vanes.

Jabwa
March 13th, 2005, 06:16 PM
We have noted the same phenomenon in the shop. My theory is that it involves the cam (lever arm). Some bows will shoot heavy arrows faster than other bows, but the situation can be reversed when light arrows are used. This has to do with the lever arm: think of a playground teeter totter; if the end where the force is applied (the cable) is short relative to the end where the object is being propelled (the bowstring) the speed will be high, but the force low. This case would work well for a light weight (arrow) but not so good for a heavy weight (arrow).

2ndchance
March 13th, 2005, 07:09 PM
are you using a radachron??


i have no experience with them but have read several posts on how innacurate they are.

azone5
March 13th, 2005, 08:34 PM
Yes, it is a Radarchron. I'm aware of its limitations. However, there seemed to be a definite pattern to the results.

archeryguyrds
March 14th, 2005, 09:33 PM
3- five inch feathers wight 5 grains, 3-five inch vanes wight about 35-45 grains. the feathed arrow will fly about 7 fps. faster but the vaned arrow will past the first arrow @ about 45 yds. does that make cents? I shoot the vanes because they last longer and don't make noise. Take care. :thumbs_up

babykeit
March 15th, 2005, 12:26 AM
Unless you are dealing with an arrow that is spined completely wrong for your setup......a lighter arrow, while not losing any significant KE, will surely not buy you any more. I am not against moderately light arrows, just pointing out a tried and true fact.

Actually, if you use an two arrows that are both properly spined for one specific bow setup, one arrow very heavy, the other arrow very light....the KE will be very close.

Any given bow setup is only capable of "X" amount of KE, regardless of what you are shooting out of it.

After lots of testing on this subject, I don`t recall ever seeing a really heavy arrow ever gaining more than 4 ft/lbs of KE over a much lighter arrow.
What if you have a arrow that is in between the very heavy and the very light. I shoot carbon impact 6000, 6500, 7500 AND THE 6500 GAVE THE BEST KE. WITH THE SAME SETUP. SO IF YOU GO WITH A LITTER ARROW YOU MAY GET A LITTLE MORE KE.

SpazAttack
March 15th, 2005, 05:01 PM
A heavier arrow will always be launched slower (FPS) than a lighter one out of the same setup. It's not rocket science. If it were not true we'd all be launching 20 lb. bricks at light speed.

You can vary the speed through a chrono by:

A) Shooting through a different part of the chrono pickup area. I've noticed as much as 5 fps difference - high vs. low.

B) How "clean" a release or the amount of backtension you get into the shot. Variations here I've noticed can make a difference of 2-3 fps.

I'd check it against another chrono.

azone5
March 15th, 2005, 07:51 PM
I do get variation based on how good my release is. It certainly shows I need more consistency. What I'm doing now is shooting each arrow ten times at each draw wt. 58#, 59#...62#. When I finish doing that, I will use a different chronograph for comparison.

Dean Lawter
March 15th, 2005, 08:45 PM
Man you got alot of hype with that one. I would say the answer to the question is that the lighter arrow that shot slower is under spined. Just go to arrow man. web sites and see spine values.

WilliamsTD
March 15th, 2005, 09:25 PM
My guess would be under spined arrow also, if the the arrow bends too much when shot you lose energy off axis to the direction of the shot.

azone5
March 15th, 2005, 11:18 PM
I've got SFA and both are just a touch overspined. Both arrows are the exact same except for vanes and feathers.

LXtuner
March 16th, 2005, 04:51 PM
Everyone knows the 5 gr/lb rule...but that's at a 30' draw. I'm a 26" draw.

I'm pretty sure the 5 gr/lb rule is for every draw length. It doesn't make a difference in the length you are. Try not being a butthead and be a little nicer. You'll never get help with your problems with that attitude. I think you owe Windwalker an apology.

2ndchance
March 16th, 2005, 05:31 PM
I'm pretty sure the 5 gr/lb rule is for every draw length. It doesn't make a difference in the length you are. Try not being a butthead and be a little nicer. You'll never get help with your problems with that attitude. I think you owe Windwalker an apology.


i was in fact thinking the same thing when i first posted. that is also part of the reason i did not stretch my mind trying to find a logical answer. :wink: