ILF Arrow Tuning Mystery

[ty_in_ND]

Hello everyone!

So, here's my story:  I finally rid myself of the training wheels. After years of shooting trad equipment at the range but taking the compound out to the woods, I sold my compound bow and forced myself to take a trad bow deer hunting.  While I already had some nice bows I liked shooting, I wanted to get an ILF setup.  So, with the funds I got selling the wheelie, I got a WF19 riser, a set of long Apex ILF limbs from Stalker Stickbows, and some T64 arrows (7.9 deflection/310 spine).  After not much tinkering, I got it shooting like a dream.  It's pulling 49 lbs at 30" (8.5" brace height and tuned for 3 under) and, after taking an inch off of the nock end of the arrow (31" shaft, not including nock or insert), my bareshafts were shooting like darts with 100 grain point.  I was hoping to get a little more up front, but the arrows were flying so well and I had some Dirt Nap DRT broadheads I wanted to try.  I went with that setup (even with the 100 grain point, the arrows are around 15% FOC, so not too shabby).  I was so confident that I took the bow out hunting and got my very first buck with it (nice little 4x4)! The arrow went right where I was looking (a little behind the heart) and he ran about 60 yards before expiring.  I was happy to say the least (my arrow even survived!).

What's the problem?  I got him in the beginning of September, so with 2 months until rifle season started, I thought I would use my free time to tinker with the arrows in order to get at least 125 grain points flying well, maybe even try for 150 grains.  Well, I put the bow together, grabbed my bareshaft with 100 grains, and was floored by the result.  It was shooting nock left... not by a little, either... It was acting as though I needed to go to a stiffer spine...  I have no idea what changed.  My limb bolts are secure, my brace height and tiller didn't change, my center shot didn't change (using the bolt CD provided with the riser) and all the shots are consistently very nock left (I shot through paper a couple times and the tears were about 4 inches long).  Just to confirm that it wasn't the arrow being too weak, I shot that same bareshaft with 100 grain point with other bows I own that are upper 40s @ 30".  They are cut to center and all had a bit of nock right arrow flight, indicating a stiff spine...

What am I missing?  To say I'm puzzled and embarrassed is an understatement, as I wouldn't have tried to go hunting with it if it was that out of tune.  I'm just thankful it was a close shot and the fletchings were compensating enough for the tuning issues (that is, if the bow was out of tune with the arrow when I went hunting with it... hopefully the issue started after my hunt).  Any thoughts on the matter would be much appreciated!

[moebow]

I'm willing to bet you have WAY, WAY too stiff of a shaft!!!!  Like WAY TOO STIFF!!  I'd be recommending shafts in the .500 spine range.  Then you should be working with 125 grain points, few recurve shooters would be using 100 grain points, that's a compound point weight.  You are getting a FALSE weak with bare shafts and 100 grain points.  In the recurve, longbow (trad) world, 310 spine is for 100# plus bows.  Also, unless your form and execution are 100% spot on, bare shafts only show your form and little regarding tune.

Arne

[ty_in_ND]

Thanks for your input, Arne! I do have some 500 spine arrows I can try out. I'll also try some heavy points on the T64s. To be honest, that's what I was trying to shoot for and was expecting to tune. I use 500s with 125s grains and 400s with 150 grains with my other recurves, so I was very surprised with how setting up the ILF recurve went. I was chalking up the 100 grain point working to the fact that the arrow is tapered, so it has a bit of weight in the front to begin with.

While I'll not rule out form issues, and I know accuracy and consistency doesn't necessarily mean I have good form, I thought I had good accuracy and consistency with my other bows and with the ILF... But, it's kind hard to fix form issues over the web, but making adjustments to the equipment would be a little easier...

[Alexander Traditional]

I have to agree with Arne. It would be impossible to make those shafts  work. I find 500 spine to be very versatile.

[ty_in_ND]

Well, I dusted off my Easton ST Epics in 500 spine (total length 31.25 from nock valley to end of insert) with 125 grain point and Kota Kill'um (48# @ 30").  Bare shafts and fletched arrows flew perfectly.  I know I probably should have gone with this setup, but the WF19 sang its siren song and I couldn't resist it! :P

I proceed to shoot these arrows through the WF19/Apex ILF combo.  The arrows were flying exactly like the T64 arrows: weak spined.  The fletched arrows visibly fly side to side before straightening out and the bare shaft is the same approximate 4" nock left.  I know the bow weighs 1 lb more and it's set to center shot (vs the Kota being about 1/8" from center with the calfskin strike plate), but I tried putting 100 grain point on the 500 spine arrow.  Still weak.  Then I try all sorts of combos of arrow spines and point weights (500, 400, 330, the T64, and 100, 125, 145, 175, 225, and 300 grain points).  Now, I didn't put the 300 grain point on the 500 spine arrow, but every safe combination I did all ends the same: nock left.

I'm at a loss.  I don't think it's the arrows, as they behave as they should out of other bows.  I kinda don't think it's me, because I can get the other bows and arrows to shoot well.  Good thing I have about 11 months to get things figured out before the next bow season begins! 

[JDunlap]

I had the same type thing with my ILF. I couldn't get any arrows to fly correctly. I had to go with an elevated NAP rest...the adjustability made the difference.

[McDave]

Try the WF19 at the same 1/8” from center as the Kota, and see what happens.

[ty_in_ND]

Try the WF19 at the same 1/8” from center as the Kota, and see what happens.

D'oh! I should have thought of that... Well, I'm settled in for the night. I'll try it tomorrow. I might even adjust the bow so it's as similar to the Kota as I can get in regards to poundage and tiller.

[ty_in_ND]

Quick update: I didn't get a chance to mess around with the WF19, but I did reaffirm the saying "experience is a brutal teacher". I played around with an arrow spine calculator and it was saying for a 300 spine arrow, for my Kota I should use a 300 grain tip. I took the T64 shaft and put a 300 grain point on it. It flew beautifully. I then shot it going to about 2/3 draw. If flew nock left.

After reading Arne's reply, I briefly remember reading about false spine reactions a long time ago, but I never experienced it as I was always fairly close to the correct spine and point weight. I don't really know why those arrows "worked" initially, but at least that part of the mystery is cleared up!