Tip weight vs. arrow spine

[DaveV]

I'm shooting a new 35 lb longbow with wooden arrows (required) and I find it difficult to find arrows spined for weights below 40 or so.

I have a couple dozen arrows, bought when I was shooting 40 lbs, 5/16 full length with 100gr tips. On this new bow they're flying nock right, making me think they're a bit heavy for this new bow. What sort of spine change would I expect if I went up to 125? I'd hate to buy all new arrows if I don't have to.

[Dave Lay]

nock right... right handed shooter?? they sound stiff  put a heavier point on and try it  25 grains may do it depending on the amount of kick your having but i bet ya have to go a bit heavier..

[DaveV]

Yes, right handed shooter. I know they're too long for my D/L, but don't want to stiffen them anymore than they already are.

I like 5/16" shafts, but with 160 grain points they stick out from the shaft. I have not seen heavy 5/16" glue-on target points for years. What I did when I was using 5/16" laminated birch arrows to get the point wieght up, was to glue on 160s that were tapered and shortened on the back with a grinder. I hit right around 145 with them.  Unless you shooting at straw bails, standard points that are wider than the shaft will hang up when pulling them out of the target.

[DaveV]

I think I'll just swap out a few for 125gr tips and do an A/B comparison. Like you, I find it hard to find 5/16 tips in any weight higher than 125. It may not be enough, but at least it'll be closer.

[TOEJAMMER]

You can add some lead in the 125 grain tip to bring up the weight.  Wouldn't take much to get it 20 grains heavier.  If need be, you can shorten the taper as you would when using broadheads with attachable bleeders to give you more space for added weight.

[DaveV]

Interesting idea. Thanks!

[Orion]

If your 5/16 arrows are spined 40#, and you're drawing 28 inches, the arrows should work for you.  Most bows will handle spines heavier than bow weight. The 125 grain points should bring them in line. Does the bow have a thick strike plate on it?  If so, might go to a thinner material.  A lower brace height might also help, unless it's too low already and the arrow is kicking off the bow giving you a false reading.

[slowbowjoe]

Full length shafts will have a dynamic spine 10# less than the rated spine, so your arrows are probably pretty soft spine to start. What sort of longbow are you currently shooting? Your draw length? How close to center cut is your present bow?

Have you tried going to a higher brace?

[DaveV]

All good questions.... I haven't had a lot of time to shoot it yet as it just arrived last weekend.  I can see the arrows fly tail right the whole way to the target. The arrows are 5/16" PO Cedar with 5" RT Helical feathers with 100gr tips.  

The bow is a Toelke Whip, 36# at 28". Brace height at his recommended 7 5/8" Bow is cut not quite to center. Strike plate is his stock thin leather pad on both side and shelf.

My actual D/L might not be as long as it used to be. It was 29" on compound with a high wrist, probably 27" or so on this bow. I'm also playing with finding a better anchor than my sight shooting under chin anchor I was using. That'll change the D/L as well.

I'm pretty thorough about A/B testing, changing only one thing at a time and logging the results. Tips are easy to change, and I have a bag of 125's already. I was just wondering in advance if there was a general rule of thumb as to how much change to expect.

[slowbowjoe]

25 grains heavier will lower the dynamic spine by about 5 lbs.
My wife shoots a whip, 40#@28. With a 27" draw, 40" spine, 28.5" long, shot well for her. She now draws 28", and spines around 50, 28" arrow, shoot well.
I like A/B testing too; only trouble is you may be getting a "false reading", as mentioned above.

[DaveV]

Thanks Joe. That's the sort of info I was initially looking for. All the other suggestions are good too. I'm sure I can find a combination that works well with my new toy.

[ChuckC]

Just a thought.  Are you shooting outside ?  Is it windy ?

CHuckC