How much more spine when adding 100gr to tip?

[Wandering Archer]

So I currently shoot a 40# longbow with 40-45# cedar shafts and 125gr field points for 3D shoots.
I just got my hunting license, so I need to get some broadheads set up. I want to use the Tuffhead broad heads that are 225gr.
My 40-45# shafts are cut down to the max for my draw length, so I will definately need heavier spined shafts. I'm just not sure if going to 45-50# will be enough, or if I need to go as high as 55-60#.
I tried to search, but came up empty handed. Maybe I'm just not using the right words?

Can anyone help me at least get a ballpark so I don't order a dozen shafts just to find they don't work?


P.S. are there not enough trad hunters in CA to warrent a CA subforum? That's too bad, 'cause I'm new at this so it looks like it's going to be a lot of trial and error learning how to hunt.

[gonefishing600]

If it where me, I would order a test pack of three of the next spine up, at different lengths.

[moebow]

Stingray,

First, wood doesn't really like EFOC very much!  Historically 125 to about 160 grain heads were/are used on wood.  Rhetorical question for you. When you break one of your current arrows, where does it usually break?  Right behind the point - right?  If that is where it breaks with just a 125, imagine the stress of a 225 grain head.

That said, the "old" 5# rule of thumb applies for INITIAL consideration.  That is 5# static spine increase for every 30 grains of point increase.  So you are looking at needing in the area of 80-85 or 85-90 spined wood shafts.  Just a ball park but probably fairly close. Your thought about the 55-60 isn't even close IMO.

Kind of puzzled too as to why you want such a heavy head?  Do you just "like" the looks or is there some reason?

Arne

[gringol]

You are probably not going to like the rainbow trajectory you'll get if you put a 225 grn head on a 500 grn shaft shot from a 40# bow.  Sure it'll hit like a cruise missile, but you'll need a ballistics chart to calculate where it'll hit.

I'm with moe on this.  Wood does much better with heads around 125 to 160.

[moebow]

OPPPPPSSS!!!  Miscalculated!!  Adding 100 grains should increase your spine requirement about 15-20# so you'll need spines in the 55-60 range - as you said.

My bad!

Arne

PS., would still ask why you want to go so high in point weight?

[snag]

With a 40# bow you really only need, and will benefit from, heads in the 125-150 gr range in my opinion.  I shoot a longbow that is 62# and shoot the 190gr Tuffhead with it.
There is a point, with wood arrows, where you can go to far with point weight.

[Wandering Archer]

Well, glad I asked before I started ordering stuff.

Moebow: Haha, you had me double checking my math there for a second. Well, being new to hunting and broadheads, all my knowledge at this point has to come from online research. So far, the best information I've come across is Dr. Ed Ashby's article. After reading that, and trying to find a broadhead that best fits those recomendations led me to tuffhead. However, looking some more, it seems Zipper makes a Grizzly broadhead that is otherwise pretty similar and is available in 120 and 130 grains.

Yes, I probably wouldn't like the rainbow trajectory. I do like how my arrows fly with the 125gr field tips I'm using. It would be nice if I could just replace a couple of my field tips with a broadhead.

So, it seems everyone is talking me into staying with the 125gr. So,I guess I'll look at getting some 120gr grizzlies?

Any other suggestions for single bevel, two blade broadheads that come in 125 gr.?

[Jack Denbow]

My experience has shown you need to go up 5# for every 50gr. you add up front. At least that works for me. So if you want to go up 100gr. 50-55 should work. You could order a test kit check it out. At hunting distance, 20 yds. or less, you won't see any difference in trajectory or point of impact unless you drop your bow arm to see the flight of the arrow.
Jack