11 replies to this topic

[hrymanback]

Hi all Im sure this has been mentioned somewhere in here but what is the formula used to determined weight grains for broad heads? I have to switch heads this year the old ones I used are to expensive so Im gonna try a fixed blade from the mechanical heads I used to use. I know its based on pounds and the individual. Im pulling 60 pounds from my Mathews. Thanks..... 

[Doc]

I'm drawing a blank on your question. I guess I never heard of the kind of formula you are talking about. Usually, the broadhead weight that you choose, based on speed concerns with light heads or kinetic energy considerations for penetration when choosing a heavy head is compensated for by the spine of the shaft that you use. Maybe (probably), I am misunderstanding the question.

Doc

[nyslowhand]

I started to respond, but was confused like Doc was!
Obvious, stupid question would be; Isn't it strictly a wgt match to old mechanical to any new fixed broadhead, ie; 100 g to 100g?

Before I did find a formula for FOC, is this what you are referring to? New an arrow w/broadhead all setup to calculate if it is good.
http://www.bowhuntin...oadhead_flight/

Easton has a calculator you can input different broadhead wgts and the then try to match their brand of choice to what you currently have.
http://www.eastonarc...ducts/selection

Other than than, I'm at a loss!! :-[

[fairchaser]

I often wondered about "grain" units myself. What I learned is that it was originally based on a single seed back when technology was scarce. It has since been redefined and is now the equivalent of 7,000 grains = 1 lb, 1grain=.0648grams and .1pound=700grains.

I like 100grain broad heads because they offer good penetration and fly straighter a little longer than 125grain broadheads.

[rock]

what is your draw length how long are your arrow, what size arrows then i can help you out you can shoot a 400 spine arrow at 60# depending on lenght a lighter tip will make a light spined arrow stiffer

[hrymanback]

Hi all thanks again for reading this post. Ill try to explain this a little different so I am not confusing anyone. Years ago in a local bow shop there was a poster I believe it was from easton a graff that showed what weight grain heads that you should be shooting. I cant remember what that formula was if it was poundage (FPS) or draw length. The reason why I am asking because the heads I used for years is a very light head and I would like to switch to something different. I'm going from a mechanical to a fix blade AT LEAST I'M GONNA TRY LOL. I have tried fixed blades before and they were never as forgiving as a mechanical. So this time around I would like to try to match up the proper grains to what I shoot. I am currently unemployed at the moment so 30 dollars for the heads I used for years doesn't seem feasible at this time.

Nyslowhand.... Thanks for the links im gonna dig into the easton one a little deeper

To answer rock's question I am at a 26 draw length and my arrows at a 28. My arrows are a gold tip graphite XT 5575. I don't know what FPS I'm shooting at. 
   

Thanks again for your help......

[Doewhacker]

I have never heard of a chart like that either. Personally I shoot a 75gr Muzzy three blade and have alot of success with them, with your arrow you may want the 100gr. Just remember to match the field points to the weight of what ever broad head you choose, it will make set up easier. And you could shoot a real heavy head if you wanted to, the arrow will just drop more in that case.

[biggamefish]

    Hry I would try to stay with the same grian broad head that you are using.  Ex if you are using a 100grain mech broadhead go with a 100 grain fixed.  I think you will have the most success with that.

[hrymanback]

Thanks All the original head I used was 75g I'm looking at a 100g fixed blade . O well i guess ill stick with the plane and drop the 100g on and do some adjustment's.  Thanks again

[rock]

100 grain is a good weight for your set up i think with a 75 grain fixed you would have problems getting proper flight, tune your bheads make sure they spin grab them by the knock and spin them if you have a little woble take them at a little bit of an angle apply a little pressure and spin again if you need help broad head tuneing dont be shy fixed blades can be hell to get to fly with field point but a few adjustments should get you real close good luck

[sweet old bill]

If you are using a compound bow most use a 100 gr point or Bh.

No when you talk to a trad hunter they use 125 gr point and some have them up a 225 gr. Tis decreases the speed of the arrow, but they are looking for increase in front of center and the weight up front will help them achieve increased peneration. They now sell brass inserts of 50 or 100 gr that increase the FOC and then they add the BH or point and that can give you up to 225 gr.

[nybuckboy]

Try a 6 pack of Magnus Snuffer 2 blade 100 gr for about $35. Tough and lifetime gauranteed. Will go through bone and cut on contact.