I got a new set of arrows the other day and today I finally got around to doing some bare shaft tuning with my recurve. I got Gold Tip Traditional Classic XT's in 400 spine. I had them cut to 29", but as I kind of expected, they turned out to be too weak with the front end setup I wanted to use.
The GT Traditional Classics come with a 78-grain insert that can accomodate GT's screw-in weight system. These weights screw in the back end of the insert, and are installed through the nock-end of the arrow with a long allen wrench that GT sells separately. The XT version of the Classics also come with a black, 14-grain, "ballistic collar" which slides over the front end of the arrow. The ballistic tip is not glued in place... It is simply held on by screwing down the field point or broadhead.
Insert and collar before installing...
20 and 10-grain weights...
So I started with a 29" arrow shaft, a 150-grain field point, and the GT nock and ballistic collar. I wanted to add a 20-grain weight as well, and after doing so I was getting a consistent nock-left flight with the bare shafts, indicating a weak dynamic spine of the arrow. From there I started taking length off of the back end of the arrow, 1/4" at a time... and I played with both 10 and 20-grain weights until I dialed it in with good, straight arrow flight. What I finally settled on was a 28" arrow shaft, the insert and ballistic collar, and a 20-grain weight on the inside. Spine-wise, my arrow flight couldn't be much better... But I think I do have to adjust my nock height on my string just a bit. I had Black Widow take some weight off my limbs, and after I adjusted brace height I never did adjust my nock height... so I expected it to be off some.
Just to put my mind at ease, I visited the 3Rivers Archery website and utilized their online dynamic spine calculator tool. I plugged in my final numbers and according to their calculator I am nearly dead nuts where it should be. And with over 19% FOC to boot. I'll take it.
I'm really looking forward to putting some wraps and feathers on these puppies and slinging some broadheads.