An offer to help

[GoldTip]

Todd thanks a lot for the info regarding my buddies Diamond Marquis, and yes it is a 2008.  I have thought his spine might be a bit weak but he gets good groups and it paper tunes well.  Thanks again.

[low97ram]

hey todd..if you got time could you run this:

09 bowtech carnivore
65lb 28" draw  65% letoff
100 grain broadheads (slick trick mag)
3" vanes   beeman ics hunters 400 (cut 26 5/8 w/o noc, 27 3/8 with)
hostage rest

if you need anything else let me know

thanks
pete

[Todd_ID]

hey todd..if you got time could you run this:

09 bowtech carnivore
65lb 28" draw  65% letoff
100 grain broadheads (slick trick mag)
3" vanes   beeman ics hunters 400 (cut 26 5/8 w/o noc, 27 3/8 with)
hostage rest

if you need anything else let me know

thanks
pete

You didn't mention which one it was 31, 34, or 37, so I ran the numbers on the 31 and the 34, since the 37 was intended to be a target and/or finger shooter's model.  The numbers for the Carnivore 31 and 34 with your specs: recommended spine is .429, so the 400's are good.  271 fps, 11.2% FOC, 63.4 ft-lbs, 389 grain arrow.  I think the database must have used Ross' range of IBO speeds as a starting point for speeds and performance with both bows because both showed the same performance.  Meaning that Ross lists the IBO speed of both bows as a range of 312-320.  The 31 should be a bit faster than the 34, maybe like 3-5 fps.  My input is that your arrow is pretty darn light and 125 grain heads should help penetration with less than desirable shots.  The numbers with 125 grain heads: recommended spine .413, so the 400's are still good, 265 fps, 13.53% FOC, 65 ft-lbs, 414 grain arrow.

Penetration ability is best measured in momentum at the target.  The momentum for the 125 grain heads is .4466, and the momentum for the 100 grain heads is .4277, both at 50 yards.  That's a 5% gain in energy delivered to the shoulder blade you are trying to break through, and, in my mind, is probably worth considering when you need to buy new broadheads.  Stick with what you know and shoot well, but if you are thinking about changing or are out of broadheads, then these are the numbers to inform the decision.

Arrow Drop 20-50, KE at 50
100 gr: 40", 53 ft-lbs
125 gr: 41.7", 54.5 ft-lbs

[low97ram]

ya...sorry about that, its 31.  09 was first year bowtech took it back from ross so they prob did use their IBO.  good idea though to switch broadheads.  thanks for the assist.


pete

[konrad]

Sounds interesting!
07 Bear Truth (hard cam)
60 pound draw
29 inch shaft
27 inch draw length
2 inch Blazers

The question is: What spine arrow and weight broadhead will give me a 19% FOC balance point?

I currently use a 2413 with 100 grain points, Bohnig signature nocks and 2 inch blazers.
My FOC is almost 11%.

Thanks for the help,
Konrad

[Todd_ID]

Sounds interesting!
07 Bear Truth (hard cam)
60 pound draw
29 inch shaft
27 inch draw length
2 inch Blazers

The question is: What spine arrow and weight broadhead will give me a 19% FOC balance point?

I currently use a 2413 with 100 grain points, Bohnig signature nocks and 2 inch blazers.
My FOC is almost 11%.

Thanks for the help,
Konrad

Your current setup: Recommended spine: .434, your spine: .365, so it's off the charts stiff.  The numbers: 231 fps, 10.68% FOC, 58.1 ft-lbs KE, 489.5 grain arrow.  Arrow drop 20-50: 58", KE at 50: 47.1 ft-lbs

To get above 19% FOC....You can stay with your current arrows and unglue the inserts and cut them to 28" (too weak at 29") and use a 225 grain broadhead.  I'm guessing you got the >19% from Dr. Ashby's research on penetration, and this is what he used to get that FOC:  Grizzly broadheads and steel weight adapters.  I followed the same logic this year and bought from these guys with no problems, but I haven't sent one through an elk yet to give you a report, but I can tell you that they get sharper than ****:
http://www.braveheartarchery.us/new_page_5.htm
http://www.braveheartarchery.us/new_page_23.htm

With your newly cut 28" 2413 arrows and 225 grain broadhead, then the recommended spine becomes .369, and your arrows are .365, so you're good there.  The numbers for this new arrow: 207.8 fps, 19.11% FOC, 57.9 ft-lbs KE, and 604 grain arrow.  Arrow drop 20-50, KE @ 50: 73.1", 47.1 ft-lbs.

To go with a carbon, I'll pick a weight forward arrow by design, Carbon Express Maxima Hunter, and the best broadhead made, Silver Flames.  For a 29" arrow and 210 grain Silver Flames, the recommended spine would be .373, and the Maxima Hunter 350's are .337 spine, so they'd be stiff but should work just fine.  The numbers for this setup: 226.6 fps, 19.43% FOC, 58.4 ft-lbs KE, 512 grain arrow.  Arrow drop 20-50, KE at 50: 59.8", 48.6 ft-lbs.

Good luck in your pursuit!

[littlebuf]

i wanna play, tho i dont know what spine arrow i currantly have. here goes

07 bowtech commander
30 inch draw-Dloop
70/72 pound draw
125 grain shuttle T's
3-3.15 quik spin vains
LT cheeta 300 carbon arrows
those pretty see through green knocks  
307 with a IBO
274-278 with hunting wieght arrows



what da ya say

[NWWABOWHNTR]

My friend shoots the Mathews (Hard time calling him a friend now  ) XLR8 Monster,  70# (set at 65) 30" DL, currently shooting Easton 2216 Super Slams, cut to 31", 100 grain tips.  I have advised him these seem to be heavy and to switch to a carbon,  such as ST Epics.  Could you run this for him?  Thanks!

[Todd_ID]

i wanna play, tho i dont know what spine arrow i currantly have. here goes

07 bowtech commander
30 inch draw-Dloop
70/72 pound draw
125 grain shuttle T's
3-3.15 quik spin vains
LT cheeta 300 carbon arrows
those pretty see through green knocks  
307 with a IBO
274-278 with hunting wieght arrows



what da ya say

I say it takes a big dog to weigh a ton, and an even bigger one to **** a ton!

There ends the philosophy lesson.  I'm guessing that you mean 307 with an IBO arrow, since that's what the program came up with, also.  I'm also guessing that you mean CT Cheetah, as in Carbon Tech, so that's what I used.  However, the CT Cheetah at 29" show as weighing 402 grains and flying at 296, and it took a 502 grain arrow to slow your bow down to the quoted 276 FPS.  So my thoughts are this: you know the speed of your hunting arrows, which are not CT Cheetah's, but you want to know the numbers on your 3D/target arrows.  So that's what I can do. Also, I didn't see a length on the arrows, so I'm going to guess it at 29".  Any of these assumptions will change the numbers some, so let me know which assumptions I made that are way out of line, and I can run it again.  The numbers for a CT Cheetah 55/80 (.330 spine) and 125 grain heads: recommended spine is .321, so you're good there, 294 fps, 12.22% FOC, 79.74 ft-lbs KE, 414.5 grain arrow.

Arrow Drop 20-50, KE @ 50
33", 65.7 ft-lbs

Let me know which assumptions are wrong, and I'll let you know what the changes are.

[Todd_ID]

My friend shoots the Mathews (Hard time calling him a friend now  ) XLR8 Monster,  70# (set at 65) 30" DL, currently shooting Easton 2216 Super Slams, cut to 31", 100 grain tips.  I have advised him these seem to be heavy and to switch to a carbon,  such as ST Epics.  Could you run this for him?  Thanks!

I can do that.  The numbers for his current arrows: recommended spine is .269, and the 2216's are .376 spine, so he's WAY underspined, 303 fps, 9.1% FOC, 111.1 ft-lbs KE, 545.1 grain arrows.  Man, I don't know about switching to carbon just because those are heavy because that bow is simply laying the lumber to the critters.  I'd advise switching arrows to get the proper spine because they aren't flying well and to get a heavier arrow to slow it down to a more controllable speed, but I don't know if either of these are concerns for him.  The complete lack of spine that arrow has versus what is needed, however, is something that probably should be addressed for safety reasons alone: off-the-charts stiff isn't a major problem, but off-the-charts weak like this is can explode arrows.  Here's a better aluminum in the right spine: 2613's at 30" and 125 grain heads look good to me: .265 spine, 293 fps, 11.9% FOC, 113 ft-lbs KE, 592 grain arrows.   To get the right spine in carbon, there're only 2 made: GrizzlyStiks and Easton Axis FMJ Dangerous Game, so I'll do it with the Axis DG 250's and 125 grain heads.  Recommended spine at 31" is .237, so that'll work with those arrows being .250 spine, 263 fps, 10.6% FOC, 113.6 ft-lbs KE, 739.3 grain arrow.

I went to the 125 grain heads because the FOC was so small with the 100 grain heads.

Arrow Drop 20-50, KE at 50
2216 w/ 100 grain heads: 31.1", 90.5 ft-lbs
2613 w/ 125 grain heads: 34", 90.1 ft-lbs
Axis w/ 125 grain heads: 43", 93.7 ft-lbs

[littlebuf]

yes the IBO i was referring to was the chrony on a IBO arrow, all be it a too short IBO arrow. the other speed i mentioned was with my field points, i have not had my shuttle T's chrony'd. i put them on my digital scale and they weigh 438.6grains. i forgot to measure them but i know when i had them cut there was not much to cut off so 29 or maybe a little longer.

[Todd_ID]

yes the IBO i was referring to was the chrony on a IBO arrow, all be it a too short IBO arrow. the other speed i mentioned was with my field points, i have not had my shuttle T's chrony'd. i put them on my digital scale and they weigh 438.6grains. i forgot to measure them but i know when i had them cut there was not much to cut off so 29 or maybe a little longer.

I'm still missing something if you weighed the Carbon Tech Cheetah arrows with 125 grain points at 438.6 grains, unless you are shooting a 33.5" shaft, and I think they come in 31" shaft length max.  I came up with 402 grains with a 29" shaft and 125 grain points.  Is there an insert weight or nock adapter that I don't know about?  My wife's CT Cheetah's use standard nocks and the normal CT insert, but maybe you've got something else?  Look over my results post for you and see if I screwed something up, because the speed shouldn't be that far off, maybe 1 or 2 fps, but not 20 fps.

[littlebuf]

pulled this off a search-

"They are made by Carbon Tech which is McKinney's company. There are two versions of the Cheetah. The Cheetah Hunter and the Cheetah 3D. The latter are about $40/doz more - supposed to be tighter tollerance.

These shafts are one of the lighter weight of the higher end carbon shafts. They are even lighter than Easton's Lightspeed. 400 spine Cheetah goes 6.4g/inch while the 400 Lightspeed runs 7.4g/inch.

I have been told McKinney's carbon arrows are among the best as to spine, as well as weight and straightness. According to Limbwalker, consistant spine may be the most important."





im pretty sure its a LT on the shaft if its a C it would take some imagination to see it as one    just measured the arrows at 28 7/8 from tip insert to knock. maybe the chrony was off 

[Todd_ID]

im pretty sure its a LT on the shaft if its a C it would take some imagination to see it as one    just measured the arrows at 28 7/8 from tip insert to knock. maybe the chrony was off 

I know the symbol you're talking about, and it is a C, just a weird one.  No big deal.  The quote you had off the search is correct; they are about the best for consistency of spine.  I hate to say it, but it's a good chance that the chrony was off.  The way to tell would be to use the arrow drop numbers that I gave you above.  Shoot at a point that is 33" above the center dot of your target from 50 yards with your 20 yard pin.  The arrow should hit the center of the target if the software is correct and should be significantly lower if your chrony numbers are right.

[littlebuf]

thanks for the help todd ill give it a try and let ya know