Theoretical Spine Question

[tim roberts]

Thought I had this figured out sometime ago, but recently it came to my attention that I am all messed up, and confused...........
Recently I picked up a 52" recurve that is 55# @ 25".  Since I have a bunch of the Beman MFX 400's I was hoping to be able to shoot those shafts.  My shafts are cut at 29" and a 145gr. field point is showing a bit weak bare shafting, I would like to go up to 215grs up front, since I only draw 25", is that 4" enough to cut off that it will stiffen the shaft enough for that much weight, or will I have to go to a 340 spine?
Thanks,

[drewsbow]

I would think you should be ok.

[Buckeye Trad Hunter]

4" will drastically stiffen the spine of a carbon arrow.  I would suggest cutting them 1/4" at a time and shooting to see where that puts you each time you make a cut.

[Friend]

Possibly obtaining some false readings. Having a field pt test kit may prove advantageous in order to run some higher and/or lower weighted points prior to cutting.

[JRY309]

When I tune my carbon I like alittle weak when bareshaft,so the feathers will stiffen up the arrow.I you want to use more upfront weight I only trim a 1/4" at a time with carbons.Carbons to me seem more effected by length then weight.They do stiffen rapidly when trim the length when you get close.

[tim roberts]

Friend,
I have tried various field points.
Even when shooting with feathers it is showing weak.  Bare shaft is a little better than fletched?
Thanks,

[JimB]

You can't cut 4" off because that would put the broadhead right at your hand.3 inches would be more like it and that would stiffen them a lot.

[Shawn Leonard]

Sorry but those arrows should not be weak even with 225 grains up front. I used to shoot 62-63# at my 28.5" draw recurves(high performance) and shot .400 spine arrows with 225 up front and cut them 29.5"s bop. I believe you are getting a false reading. One of the best shooters I know on this site shoots 29.75" BOP .400 spine shafts out of his 63# Kwyk Styk with 250-275 grains up front. You should be able to shoot a .500 spine cut to 26.5"s with 225 up front and that will get you darn close. Another example, I am shooting 52#s at 28.5"s and shooting a 29.5" .500 spine carbon cut to 29.5"s with 190 grains up front. Shawn

[JimB]

Stu's calculater says you are about 10 lbs too stiff at 29 with a 145 gr point.You know it is possible to be so stiff that the arrow bounces off the edge of the shelf and impacts,giving a false weak indication?This could be happening.Don't cut anything just yet.

When you say you have tried various point weights,what is the heaviest?You may not have gone heavy enough.Did you try 200? Don't be afraid to put the weight on.If it IS a false weak indication,eventually,a heavier point will prove that.You have to have a bunch on hand to sort it out.

[tim roberts]

More weight?
It seems that the heavier up front I go the more to the right the shaft goes.  I'm lost..............

[Friend]

You may wish to verify your bow arm's response at release and thru conclusion. Your bow arm response can tell you much about the shot execution. At the shot and thru conclusion, the bow should naturally move directly toward the intended target and then fall to the left for a rt handed shooter.

[metsastaja]

Tim: try this article see if it helps.
 http://www.bowmaker.net/index2.htm
 
The bow may be miss marked 55@25 seems a bit strange. I would put it on a scale or take it to a shop to confirm.

Check you shelf and strike plate materials. Are the worn?

[warden415]

I would say you are too stiff also based on my findings. I also have a 25" draw. I'm pulling a little less weight but have 250 gn up front and am shooting a carbon with a little over .500 spine and about 29" steve