I am by no means a mathematician OR a rocket scientist...but I aspire to play one on TV. That being said, It takes time for momentum to build, and most YouTube info is geared towards compound bows >65# and distances >30 yards.
Your choice is a heavy arrow with less FOC, or same spine low GPI and higher FOC. What'll it be???
For example: 40-45# bow, 500sp, 465gr with 19% foc vs: 500sp, 435gr, 22%
A third option is "moo" point.
Quote from: BAbassangler on November 29, 2025, 01:30:46 PMI am by no means a mathematician OR a rocket scientist...but I aspire to play one on TV. That being said, It takes time for momentum to build.
Like a rocket, an arrow reaches its maximum momentum when it reaches its maximum velocity. Unlike a rocket, an arrow does not have any internal fuel, so reaches its maximum velocity as soon as it leaves the string.
Excuse my ignorance, but what is "moo" point?
The one that flies the best :archer2:
Quote from: durp on November 29, 2025, 03:40:20 PMThe one that flies the best :archer2:
Right on! Personally I just start with the arrow I want to shoot and try and build up from there. 11-12 grains per pound as the goal. Example my long bow I shoot a .204 ID arrow that has 6.7 gpi. 80 grain inserts and 150 grain BH gets to 460 +/- grain total. Never bothered figuring foc. I was looking for lighter faster and these fly like lasers.
Joey Tribiani from 'Friends', wasn't the brightest guy and didn't know moot. Thanks for the rocketry crash course. I've been leaning towards "moo", or faster is better, as the ft-lbs, in the 3Rivers calculator are near identical, might as well get the speed as long as quiet enough.
Right on, right on, Flemish Twister and Durp. I've jumped up 1 and 2 spines and they never fly as good when they're the same length, and always end up around 700gr. They hit like a freight train, and I get to shoot bigger heads, but they just don't seem to ever bareshaft as well.
Because of my age, I'm relegated to hunting with 40-45# bows, so I have some familiarity with bows in that range. Both of your examples are close to 10 gpp, which is my preferred arrow weight for hunting. I prefer your option that uses a lighter shaft and a heavier point weight to get there, as I understand from reading Dr Ashby and others that that configuration is generally more lethal than having the weight more evenly distributed along the arrow. However, your example are close enough that I'll go with "moo" point.
Thank you McDave. Too old to go back to school, this'll do. I think I got lost in the 'heavier arrows shed less momentum' world. Doesn't seem to make much difference at 0-7. The data for 700 grain arrows seemed to be more of a bang for your buck with ft#'s. I think I'll carry one of those for CQB ambush points, with a 3 blade. Thanks again!
Bow- Covert Hunter 41@28
Arrow- Carnivore 400...100 gn insert...250 gn... 1 ¼ 3-blade VPA
...572 Tot Arrow weight...13.95 gpp...29% FOC
***Excellent Bare shaft flight...tested to 30 yards
All three deer this season had pass thru's, nice blood trails and easy recovery
Typical arrow build and results used the past 15 years
Quote from: Friend on December 02, 2025, 06:55:35 PMBow- Covert Hunter 41@28
Arrow- Carnivore 400...100 gn insert...250 gn... 1 ¼ 3-blade VPA
...572 Tot Arrow weight...13.95 gpp...29% FOC
***Excellent Bare shaft flight...tested to 30 yards
All three deer this season had pass thru's, nice blood trails and easy recovery
Typical arrow build and results used the past 15 years
I think I need to nit-pick my setup. I can tune 500's like lasers; shoot well standing upright/bow verticle, and hunting stance with cant. My 400's, to bareshaft well, are always longer and I lose most of the gain in FOC, and only benefit from the stiffer shaft??
My 500's are 29+ half-out. Maybe there's a magic centershot adjustment that will suit me best.
Honestly.... The 500's tuned well will be more forgiving to a less than perfect release that a stiffer shaft. Foc balance is a highly controversial subject. Especially the EFOC theory's.
I went down that road years ago and didn't care for the arrow flight on EFOC arrows. Anything past 20-25 yards and they drop like a stone. A better balanced arrow with decent fletching doesn't do that nose dive the EFOC arrows do. just my experience on that...
penetration on animals have much more to do with broadhead style, sharpness, and arrow placement than anything else.... My .02 cents....
Thanks for the shared experience, Kirk. That seems to be the way I'm heading; staying in the 10-12gpp range. But life is too short to walk around with all matching arrows, lol. I will keep my 700gr lawn darts for planned 5-7 yd ambushes.
Even with how awesome the 700gr 400 flies; if I'm short on my draw or by brace needs adjusted, I get a 'click'...probably stiff clanking off the shelf, whereas my 500's can do no wrong.
Shame there aren't much to choose from in the 450 spine, my Victorys 450's spine almost identical to Axis 400.
Maybe next year try some stiffer 500's. (or weak 400's)
There's static shaft spine and dynamic shaft spine. The shaft material used for arrow making can have a vast real world shooting difference between those two types of arrow spine. This is never more true than with carbon shafts that list a huge static spine range for a huge range of trad bow holding weights. I've always had big problems tuning really stiff carbons for a 44-52 pound longbow holding weight and the answer for me is a 29" 500 carbon shaft, that's all I ever used for carbons and longbows. Woodies are a whole diff'rent story and why I have to carefully static spine each wood shaft.
Rob, I just stumbled upon your same conclusion; faked out by spending too much time on the 3R spine calculator than actual trial and error!...again.
The 500's that would spine from my 45# LB @29", are Axis with 200 total up front. Grabbed a standard diameter bareshaft from my 39# recurve and shazaam. I was able to get 260 to 275 up front. I'll spend more time with it tomorrow, but it's looking good. Around 23% and 515 to 540 grains (one is camo wrapped), 160fps. And for any future archive hunters, this was about 1/8" from center. I didn't have much success with centershot.
If you really want to get things fine tuned. I'd highly recommend using a spine tester on your bare shafts before you do anything, and get your stiff side towards the shelf...
You will be amazed how much difference the spine varies in carbon shafts just rotating them 90 degrees at a time.
Some of the economy shafts out there are all over the place in consistency, and trying to get a dozen matching shafts is almost impossible without buying 5-6 dozen shafts.... HUGE difference... They are worse than woodies in some cases...
Even the high dollar shafts with very good straightness tolerances can vary a lot in spine just rotating them on a spine tester. Also doing this eliminates bare shaft tunning every shaft.
Food for thought...
Kirk
Quote from: Kirkll on December 06, 2025, 09:04:40 PMIf you really want to get things fine tuned. I'd highly recommend using a spine tester on your bare shafts before you do anything, and get your stiff side towards the shelf...
You will be amazed how much difference the spine varies in carbon shafts just rotating them 90 degrees at a time.
Some of the economy shafts out there are all over the place in consistency, and trying to get a dozen matching shafts is almost impossible without buying 5-6 dozen shafts.... HUGE difference... They are worse than woodies in some cases...
Even the high dollar shafts with very good straightness tolerances can vary a lot in spine just rotating them on a spine tester. Also doing this eliminates bare shaft tunning every shaft.
Food for thought...
Kirk
Right on and even more important for woodies!
That would definitely be an upgrade. This year I started rolling them and marking the stiff side; going to try not to rush and bareshaft each one, nock tune if necessary. Wood would be nice to play with. I like those taper tools, and had a fascination with an article on Forgewood a long time ago...even sketched up a dowel compressor. It's probably sitting in a box with my bowpress parts from Bingham, lol. My bowyer career only made it to board and backed.