Tuning help?

[RM81]

I thought I had a handle on tuning, but I need some help.  I'm shooting an old Bear Grizzly (early 70's I think).  It's 58", 50# @28.  My draw is right around 28.5".  I'm shooting GT 3555 trads cut to 29.5 BOP.  I started out shooting 125gn points and it seemed a bit stiff, so I added a 50gn brass weight to the back of the insert.  It still seemed a bit stiff, so I added another 50gn insert weight and now I'm getting fletching contact to the riser.  Is it possible I'm actually too weak and the arrow is bouncing off the riser?  Thanks for any help.

[maineac]

Have you tried bare shaft tuning?  I am no expert on this by any means, but I have found shooting the shaft without feathers to really help me see if it is stiff or weak and adjust point weight.

[SS Snuffer]

Ya what he said, you will know 1st shot.

[Bowmania]

WOW! That's a short bow for that draw length.  What's the deflection on that arrow?  I'm guessing you'd need a 0.500, but Stu's calculator would give you a much better idea.

Bowmania

[rastaman]

According to Stu's calculator that arrow spines out at about 43lbs or so with that point weight and insert weight.  Your bow needs about 62 lbs of dynamic spine (again according to the calculator).  Your original arrow without the extra weight would have a dynamic spine of about 59 lbs.  i would say you are weak.  That was plugging in an 8 strand FF string.  With a B 50 dacron your bow would require a dynamic spine of about 55.

[NoCams]

Whip out a good sharp knife and cut the feathers off one arrow leaving the quill on the shaft. You will know IMMEDIATELY what is wrong, stiff or weak. Watch arrow flight as it comes off the bow and as it flies to the target, tail left or right. Make sure your nock point is a good 1/2 to 5/8 above center as well so you are not bouncing off the shelf as well. Once you get the spine right for good flight then you can possibly bring your nock point down if needed for up and down flight. If you shoot 3 under most have a nock point as high as 3/4" above center. What is the Bear braced at ? Should be around 8-8.5" from string to deepest part of grip. Once brace height is established and all tuning is complete keep everything the same and shoot the bareshaft to make sure all is well with both the bow and the shooter. Good form is a requirement of bareshaft tuning, not an option ! Once you get a rig shooting bareshafts repeatably if all of a sudden you cannot, then your form is usually the culprit. We shoot a bareshaft during our practice to keep everything in check. JMHO

[RM81]

Thanks for all the replies.  I do have a few bare shafts.  I did the paper test.  I was shooting about 10 yards out.  The paper was about 2 feet in front of the target.  Tail was to the right and high & I shoot RH(which is stiff and high nock?).  I'm going to try and set something up in the basement tonight and try again and then make some adjustments.

When paper tuning do I need to be closer than 10 yards to see what the arrow is doing as soon as it leaves the bow?

I do use Stu Miller's dynamic spine calculator, but one factor I'm not sure of is string material.  The bow came with the string when I bought it, so I don't know what it's made of.  Is there a way to tell the difference?

It's braced around 8 inches.  I'll double check tonight to make sure.  I'm shooting 3 under. Nock point is set at 3/8". And I'm sure my form is not great, b/c I'm new to trad.  I watched Masters of the Barebow and have been trying to use some of the info from it to apply to my form.  My anchor is pretty consistent, but I noticed that I have a dead release.  When I release, my hand/elbow don't move back at all.  I'm pretty sure I'm using back tension to hold, b/c I don't seem to have any problems holding at full draw.  I'll try to take some pictures tonight.

[**DONOTDELETE**]

I start out at 5 yards when paper tuning, I also don't do bareshaft only fletched arrows. I also hold the bow as I would when hunting.

I am right handed so for Me slight left and high nock is great. I then back up to 10 yards and check it again. If it is about the same I start fine tuning and get it to be bullet holes.

Some times I'll just flight test/tune an arrow. I start off full length and cut 1/4" off and re-shoot till it flies great once it leaves the bow.

[RM81]

Here's the photo.  Unfortunately, I only got to shoot one round.  I nicked my serving when trying to adjust the nocking point and it all came unraveled.  I didn't hurt the string, but now I have to wait to get the string serving redone.

The two on the right are bareshaft.  The three on the left are fletched.  The one on the far left is my fault.  The shot felt bad when I released it and will chalk it up to bad form.

I took out all the weights and put on 100gn points.  According to the Dynamic Spine calculator (using B50 string material which I'm still unsure of), the required spine on the bow is 63.5, and the arrow I used is 65.2.  Nock was set at 3/8", and the brace was just a little under 8".