where does broadhead weight come into play? ive always just bought what looked like a goo broadhead and now ive started to wonder what weight do i need and why? all i bow hunt for is deer i shoot around a 60lb. draw so what weight do i need? can someone explain what the different weights are for and the advantages and disadvantages of the different weights. thanks,sean

The best way is to do an F.O.C. analysis. It is a simple analysis that requires no special equipment. My advice would be to start with a 100 gr Broadhead and check your F.O.C. Then check it with a 125 gr. The calculations for my arrows follow and I shoot 100 gr Thunderheads since mechanicals are illegal in Washington State.

FRONT OF CENTER %

Arrows with a weight forward balance between 7% and 10% are the most aerodynamic.

To find your F.O.C. %

1. Measure the arrow shaft from the tip of the broadhead to the end of the nock. Divide this measurement by 2 to find the center point (i.e. 30” shaft divided by 2 = 15).
2. Mark the center point with a felt tip marker. Now balance the arrow.
3. Mark the balance point with a felt tip marker. Divide the distance between the two marks by the overall length of the arrow then multiply the result by 100. (i.e. distance between the two marks of 30’ shaft is 2.5” then 2.5 divided by30 times 100=8.33%)

When greater than 10% use a lighter broadhead
When less than 7% use a heavier broadhead.


My hunting shaft F.O.C. calculations.
Over all length: 30 7/16”
Mid Point: 30.44 / 2 =15.22” (15 7/32”)
Difference between mid point and balance point: 2.31” (2 5/16”)

Therefore F.O.C. = (2.31/30.44) X 100 = 7.59%

Since 7.59 is > 7% but < 10% my F.O.C. is acceptable and aerodynamic.

Broadhead weight!!!! FOC calculations, come on! I don' t think a calculation is the way to go. Go out and buy different weights, and just shoot them. What do you shoot best with. I was shotting 100 grain for while because I wanted more speed. Fact is I was' nt shooting very consistant. I started messing around with arrows and different grain weights. I found I shoot mcuh better with a 125 grain broadhead. My groups are much more consistent, I get better penatration, and I still get in the 290' s. It takes a little time, but lets face it, the best way to get an idea of what to shoot is to actually go out and shoot. No calculations can take into account the intagibles of shooting. Everyone shoots different and every bow is different. Shoot wth what you shoot best

there are 3 points to consider

1) I agree with dick that FOC comes into play, though I think 7 - 10 percent is a little narrow. IMO you can expect good FOC up to around 15%.

2) SPINE. You need to know where your setup and arrow spine sit. If you go to heavy or to light it can adversly effect spine and flight.

3) SPEED. Once you find the weight range your setup will work with then its up to you, if you want to milk a little more speed go on the light end.

I do agree to an extent with justhrowit, in that shooting a few heads is a good way to find out, BUT.....not everyone has access to dif heads or the money to buy a bunch of packs. So, if you do a few calculations that will get you a reasonable idea of what you need is much better than just winging it and buying 100 dollars of broadheads you may never use.

FOC is a tool. Like any tool, it' s not supposed to replace real life testing, but it' s a great place to start. For Fixed blade broadheads, I wouldn' t want my FOC under 9%, and would probably prefer 10-13%. Once you' re in the ballpark, then you' ll have to tune for spine and group tune. It' s better than just picking any weight head and hoping.

I noticed that your topic has to do with broadhead weight and not type. I agree that the FOC is an important consideration in determining this. I have found from my own experience that I prefer an FOC in the area of 13-15% for fixed bladed heads. You may be able to go down a little more to maybe 10% for mechanicals, but I don' t use them, and my experience is limited. Currently, I am shooting just over 14%. I use a few different broadheads (all fixed). My main hunting head is a magnus four blade (185 grain with insert), but I am also messing around with a 125 grain GFK Deadhead. For this head, I use an larger insert with a 50 grain weight to get the FOC to were I like it.

Here is a good place to start to check for FOC without doing your own calculations, all you need to do is click on the type of arrows that you use and fill in the rest of the info:

http://home.att.net/~sajackson/arrowtools.html

Rack hit the nail on the head on this one . Spine is very critical in getting good arrow flight , with field tips , then when you add " wings" to the front of the arrow with a broadhead it becomes all the more critical . In our quest for a fast arrow alot of us go for one with a marginal week spine , where we should be going for one with a stiffer spine , say one rated for 10 pounds heaveyer . I' ve found that its easyer to tune a broadhead equiped arrow that is slightly stiff as compared to one that is slightly weak . Another thing to consider is fletching , 3 or 4 , 4 or 5 inch feathers or vanes should be minimum , the bigger the surface area up front = the bigger the surface area in back , the point being I dont think you want to use a big 3 or 4 blade broadhead up front with 3-3 inch strait fletched vanes .