[bigracklover]

I know this should be in the tuning forum but figured it'd get more play over here so here's my question.

According to OT2 program the optimum spine for my setup is right around .400, and of course the .400 spine arrows group and paper-tuned well. Just playing around, I tried some lightweight arrows but they only came in .500 spine. They flew great, grouped great so I thought I'd shoot thru some paper and see what happened... very good tears at 8-10' so I backed up to 20' and got the same result. Then I walked-back tuned and everything was good.

How could the same setup produce the same results with two differently spined arrows? Now I'll add that these results were with fieldpoints and not broadheads and I don't plan on hunting with the incorrect spined arrows, for that I'll stick with the optimum, but I'm stumped as to why they tuned so well? Any opinions would be appreciated.

 

[Bowhuntr64]

I am not sure that is such a rare thing...I have done similar tests and had similar results. The guidlines are based on optimal results, but are not hard and fast rules. Just an additional thought, you will usuallly get better penetration in game with a stiffer arrow.

 

[redneck.archery]

what arrows did you do your testing on?

 

[bigracklover]

what arrows did you do your testing on?

Beman ICS Bowhunter 500 - 7.3 gpi - 26.5 inch shaft

 

[22jdub]

Try it with broadheads. I've had the same issue, underspined arrows flew great with field points, put a fixed blade broadhead on them and I was hitting 3" left every shot.

 

[andy1996]

I think spine is super important when shooting recurve or compound fingers because of archers paradox--the arrow bending around he riser. But for compound release shooters the only movement is up and down off of a launcher. Accoring to Archers Advantage my arrows are way stiff, but they fly awesome. I have had several conversations with the "Hammer" and he said stiffness of arrows for compunds is really relative to what kind of shooting you do. I would much rather have a stiffer arrow than a weaker one.

 

[kevinh]

as long as it shoots

The best flying broadhead I have EVER had was Beman ICS in 500 spine with 75Gr. Wasp BH's, 4" helical Flex Fletch Vanes at 75lbs. That was way off the chart but they flew fantastic and were exceptionally accurate.

The charts are just to get you in the ball park. There are so many dynamic things that can change what is THE optimum spine no chart could ever capture it.

As far as BH's and field points hitting the same, I can't say that they did or didn't. I've never been concerned with that as long as the BH's group. I never shoot FP's during hunting season anyway...

 

[bigracklover]

Thanks for the replies guys

 

[AllenRead]

Your bow probably has very good nock travel and you are not putting any torque on the grip.

When the nock is traveling straight during the power stroke, you can get good results with almost any spine with field points.

 

[WIBuckHunter]

I use .150 spine arrows out of a 60# bow for hunting and they shoot and group superbly! But on the other side, i have tried .500 out of my 60# bows and .400's grouped quite a bit better.