EFOC recipe

[cch]

I wouldn't worry about the EFOC unless you are planning on hunting cape buffalo. Just pick a good quality broadhead that you want to shoot and build your arrow around that. I like a faster arrow but shoot a 200gr head because I can use a steel insert on a grizzly or get a one piece Abowyer and know the head will not break like an alluminum ferrule will and most of my arrows are in the 500+ range. I get pass throughs on everything I shoot and I don't even know what my FOC is. But I have a fast enough arrow to take game out to 40-50yds.

[cch]

I forgot to add, if you are going to use a supper
Light arrow that they are not very durable. I really like the easton axis arrows with the small diameter and thick walls it helps with penetration and I don't think I have ever had one break from hitting an animal.

[JimB]

Originally posted by snowplow:
I see the problem JimB. I didn't know what you meant at first. I am not planning on running that Heritage 90 with .500 spine. As a matter of fact, I dont know why I included that information. It was just to say what I am currently running. I have never ran a EFOC arrow before.

I plan on getting Gold Tip Velocity shafts but I dont really know how to predict what spine I'll need.

It looks like from your prev post maybe .350-.400 spine.

My point was,you were referencing the GT .500's when you talked about 6.3 GPI.If you use GT .400's or .350's,overall weight is going to be quite a bit more than what you wanted.

Tuning should be the first priority and your shaft choice,bow etc are going to determine the finished overall weight if you truly tune.

If you want to stay in that 500+ weight range,I would get a couple Victory V Force HV's and experiment with length and point weight first.

[snowplow]

I see what you mean now JimB. Tuning is where I'll start but I am waiting on materials still. If any of you are curious, I have a spreadsheet full of number comparisons made and it looks like with a 500 spine GT Velocity I could get a max of 26% FOC @ 30" with 300 gr up front and only 508 gr total.

If I have to move up to a .400 spine, I could achieve a max of 23% FOC @ 30"with 275 up front
and 530 gr total.

The GT velocity shafts are a good amount lighter than the victory v force btw.

[Cari-bow]

Snowplow
The Victory V Force "HV" .400 are 6.4 grains per inch.
The GT Velocity .400 are 7.4 grains per inch. At least that's what my charts say. I know the Victory's are but the key here is the HV which stand for "high velocity".
I know JimB has done allot of testing with the extreme high FOC.
Abe

[snowplow]

This V force chart shows 7.2/8.0??
   Vforce HV

GT Velocity Hunters show 6.3/7.4

 GT Velocity

Please correct me if I am wrong. (especially if there is a lighter shaft to consider       )

[Cari-bow]

Snowplow
We agree with the GT chart.
On the Victory V Force HV V3 is where I have a different chart. I got mine from Lancaster Archery Supply . I have some of these arrows and the .400 are 6.4 grains per inch. The .350 are 6.8 grains per inch. Not sure if it's on there web site but the catalog has them.
They don't seem to come in the .500 spine.
Abe

[JimB]

snowplow,their site is erroneously giving the specs for V Force whether you click on V Force or V Force HV.It's just a glitch.

HV 350's are 6.7 GPI.HV 400's are 6.2 GPI

Again,you are calculating point weight arbitrarily,just to come up with a preset overall arrow weight.It doesn't work that way.

You can't have less point weight on a stiffer,.400 arrow and more point weight on a weaker.500 spine.

When things tune out,if you do tune,the stiffer shaft will have more FOC because it REQUIRES more point weight to tune.You can't predetermine the overall arrow weight.Tuning will determine that.A .500 spine,30" arrow is not going to fly well with 300 grs up front unless the sight window is cut quite a bit from center.On my bows,a 30 1/4" GT Velocity tunes with a 145 gr point-20% FOC.At 29 1/2",they tune with 175 gr point-23% FOC.

I personally would forget about overall arrow weight and see where the tuning takes you,then you can change shaft choices if you don't like the weight and to be honest,you aren't going to see any real difference in 50 or even more grains of overall arrow weight.

[Cari-bow]

Here is the chart from victory archery.
 http://www.victoryarchery.com/shaft_selection.html
Check out the first 3 sizes in red.
Vforce HV
Abe