I am shooting woodies real well out of my 68 inch deathwish longbow.  54 @ 30 inch draw.  70-74 spine arrows 31 inches, 23/64 tapered to 5/16 3 5inch helical fletch shield cut.  I am not complaining but I do not understand what is happening.  

If I use 125 heads or 160 grain heads, I get my arrows to group well, in fact I usually get 3 arrows touching at 20 yards-ish and 2 others within 2-3 inches of the tight 3.  the weights do not matter.  My point is I figure I should have some spine issues changing arrows that long with 35 grains of weight up front shouldn't I?  My string is not fast flight, nor is the bow center shot.  Can I be that lucky or is something else going on?

I have wieghed the arrows on a digital scale and the numbers do not lie.  The arrows weigh between 563 to 605 grains and all fly to same spot basically out to about 25 yards.  I ahve not tried much farther other than a few flights. I know weight by itself at hunting distance has little to do with point of impact, but I assumed it would have impacted spine in a big way.  I am not seeing that and wondered why.  

Bob.

my guess is that the 5 inch fletch with some helical is steering that arrow to where it should be. 20 yards gives a lot of time for that fletching to correct any differences in trajectory. Keep in mind I am a carbon user so I may be totally off base when it comes to wood arras.    
If the arrow shoots keep it in your quiver and don't worry about spine and all that boring stuff!

Bob: Kind of nice isn't it. Your experience isn't unusual.  It's normal. Wood is quite forgiving. There may be minute differences in where the arrow will impact, but most folks won't notice a 25-50 grain difference in point weight with wood arrows.  They will drop off a little faster past 25 yards with the heavier heads, but the difference in trajectory under that range is negligible.

There's been an explosion in interest in tuning arrows to the bow in recent years.  A lot of folks try to get down the the exact pound of spine that's optimal for their bow.  There's no doubt that there is probably one best spine weight to the pound for a bow, all other things being equal.  And carbon arrows, which come in a smaller selection of spines, might require more tuning.

What is often overlooked/forgotten, is that most bows will accommodate a fairly broad range of spines quite nicely.  Changing point weights is just changing the dynamic spine a little.  Can also change it by changing the physical weight and/or static spine and/or length of the arrow.  As long as those changes aren't dramatic and are sort of mid-range for a given bow, all of the arrows will shoot well.  They don't have to be tuned to the nth degree to fly well.

Howard Hill demonstrated this quite nicely.  As part of his shooting demonstrations, he would often collect arrows from patrons in the stands.  These (wood) arrows were different physical weights, spines, lengths, point weights, etc.,(probably way underspined for Howard's bows)  yet Howard would put one after the other in the bulls eye.  In short, at relatively close range, they all shot to where they were pointed.

Orion,

Thanks for the post, your explaination explained a lot. Now I jsut need to determine what weight broad head I will hunt with and find a broadhead that flies well and is quiet.  Tops on my list are; 125 Zwicky Black Diamond, 145 Stos, 160 Ace.  I am kinda excited to see if I shoot any of them better than the others.

Bob.

Orion I have shot arrows that should have been 'wrong' by two spine groups-and once fletched you can't tell. Thanks for the explanation.

I only shoot wood arrows and I have found that I have the same results that Orion has, with wood the spine is really not that important, unless you shoot really  weak spined arrows then you will know it.

My experience suggests that wood spine is only critical when shooting the largest of broadheads. At hunting range, weight is not critical at all. I routinely bare-shaft match with 125 grain field points, and usually can go up to 160 grains in broadheads without having to go up in spine.

Wood is very forgiving. I use 65-74# splined arrows for all of my bows that range from 54#-60#. One thing I have noticed is when I use a 5.5" fletch they all fly pretty well even with a wide range of tips (125-250gr) the smaller 4" fletch makes it harder (for me atleast) to get that wide of a range of arrows to fly the same. Yes some arrows will just not fly correctly, I will place them to the side, fine tune them and mark  them to the special weight needed to make them fly. Good record keeping and marking of specific arrows will help you in the long run,and eventually will help you narrow down the exact spine range you can shoot.

My guess is that you are ideally spined for the 160 gr and the 125 gr is within the tolerance range for being slightly overspined; which usually is fine.  As others have said - wood is tolerant and some bows especially so (window cut, rest, etc., etc.).

Most of my bows will shoot a range of spine well and weight matching is over rated. I do think matching spine in your set is a sure way to increase accuracy though.I just made up a set for my dad that were matched to 69/70 and +/- 8grs. His groups went down significantly and he thinks I have some secret. No secret, just tighter tolerances.

This is great info!! Thanks guys!  I was trying to figure out why I have 60-65's and 65-70's that fly so well out of my bow... Now I know. The 60-65's had a slight kick to the right in flight but always hit the mark within a couple of inches. I adjusted my brace height (stiffened arrow spine) and, ta-da, arrows fly like darts... AND the 65-70's STILL fly well. I am going to experiment by putting 190's on the 65-70's... from what I have read here, I think they will fly just fine  

I love the fact that everyday I learn something new on this site. Thanks guys

I have been considering woods and wasn't thrilled with the prospect of the "fine tuning" that I THOUGHT must be done at hunting distances. This thread and the replys have been eye opening.

Thanks gents. Looks like some woodies may be in my future.

Dave

I agree that minor differences in dynamic spine are not readily apparent with field points.  When you put a broadhead on the end of that shaft, the difference will be more noticeable.  One of those weights will fly and group better than the others.  That one will also penetrate better due to the straighter flight path as well.  For a hunter, it doesn't matter squat what a field tip does, broadhead flight is where the proof is in the pudding.

I found the same thing I shoot the same spine wood with 125, 145, and 160 points all fly the same I have even mixed them all up  to see if I was nuts results were the same! Try that with carbons usually another story!

Like Orion said there may be a wide range of spined shafts that once fletched they will all fly good out of your bow. But for those of us who want perfect if you were to bareshaft those different spined arrows you would see a difference if flight. Just had to say it...."bareshaft"....haha

I am experimenting with 230 grain vs 125 grain points on my doug fir.  I use a threaded adapter so I can change points quickly and easily.  Mostly I find that there is not much difference in where they land.  The high FOC with the 200 grains fly great and stick better in the flat range worn out carpet targets with better penetration.  I am planning to try 250+ grains next

Wow, that's some heavy tip weight for woodies. What spine weight are you shooting Dave?

Given your setup, I am not surprised, plus the weight difference is not too great at 20-25 yards.  If you went much further you would notice some arrows hitting lower. There is an advantage to getting weight differences to +/- a few grains, if you want to hunt varmits or ground squirrels at longer ranges.

Howard Hill said, that one could expect to be accurate on game out to 60 yards, with a 50# bow out to 50 yrds and a 60# out to 60 yrds.

Personally, I feel that weight is more critical than spine. I would rather have the weight to within 5 grains, than the spine identical. I have a number of bows that will handle a wide range in spine 50-60, or 50-65, but a 15 grain difference will be noticeable.

David,
70-75 spine wt.  Which is my expected wood arrow spine weight for the bow I shoot. 29" BOP.  Which means I draw about an inch of the screw-in adapter.
Dave