xx78 or xx75 in determining FOC

BobCo19-65 · 11-24-2003, 09:49 AM

What do you guys think. I am moving back to the 2317 aluminums from a 2613 (185 grain tip) mainly because I will be doing some elk hunting next year. I need a little better trajectory for shooting over 30 yards (I' m looking for 45 on the elk). Question is this, I can get the 2317 in either the super slam with the uni nocks or the camo hunter with the traditional type nock. I have used both in the past and don' t have a problem with either. I' ll be using a 135-145 grain tip. But I' m looking for the best highest FOC that I can get with the heads. I measured the FOC with the super slams and a 135 grain head at around 8.9 percent. Do you think that going with the xx75 with the conventional nock will get me any substantial increase of FOC? Believe it or not I' m even considering going back to a three fletched helical feathers from a four vaned offset. I don' t want to have all that much drag that the four vaned combo gave me, especially with longer shots.

ijimmy · 11-24-2003, 10:48 AM

I think if you are going with heavy foc your arrows will arch more . Flying with the front end heavy seems like the point end would be faceing more in a downward fasion during flight and therefor hit lower at distance. 8.9 is fine though some guys go up to 15 . Nothing wrong with feathers , useing 3 offset 5" and a magnus head would be a great elk setup .

BobCo19-65 · 12-01-2003, 07:52 AM

Thought I' d get a few more answers. Maybe I' ll just give easton a call. All I' m really asking is if the conventional swage type nock ends are significantly lighter then the uni-nock system.

Rangeball · 12-01-2003, 08:15 AM

Bob, have you visited bow jackson? I believe their FOC calculator lets you do both, which should tell you...

Arthur P · 12-01-2003, 08:49 AM

There isn' t enough difference between the two nock systems to make a significant change, most likely only a few tenths of a percent. Where you' ll pick up a LOT of FOC is going from 4 vanes to 3 feathers. A couple percentage points, at least.

BobCo19-65 · 12-01-2003, 09:44 AM

Thanks Art, I knew you' d have the answer. I had a few xx78 2317 shafts around and measured the difference in FOC using a 135 grain broadhead using the four vanes and three feathers.

4 4.75" vanes = 10.25% FOC
3 5" feathers = 12.75 % FOC

It' s been quite a few years since I used feathers with my compound, but if felt pretty good shooting them the other day with the broadheads. Just a little noisy.

Since it really won' t matter if I change between the XX75 and the xx78, I' ll stick to the xx78 since they are so easy to index.

Rangeball, yes, I have used the calculator in the past, however, I much more prefer calculating it myself. I have found differences in the past.

Arthur P · 12-01-2003, 12:10 PM

Shoot those feathers for a couple weeks. They quiet down when you get some of that stiff newness worked off of ' em.