Hi gang. I went shooting today and was observing my arrows porpoising as well as going left to right(paradox?). My bow is a 69" maple board self bow, drawing at 42lbs at 28". I am currently shooting a Carbon Express shaft, Stl Hunter 300 that I shot from my wheely bow(that I sold:)    ). I am wondering if these arrows are too stiff for my bow? I did cut a shelf into the bow to bring it closer to centre shot, and my nock point may not be perfect on the string. I wish to build some wood arrows soon, this would give more options as far as spine goes. If I am not wrong there isn't much difference in spine on carbons? Thanks for any input. I am having a gas shooting this bow, and made a quiver too. Into my set-up for about $30!

300 spine arrow in a 42lb bow? I would say you are most definitely over spined.

A 300 spine without crazy heavy inserts or broadheads up front is made for a 65# plus bow. You'd probably need 300+ grains up front to make that spine out right depending on length.

I think that you are way over spined.Your shooting 42#@28 on a bow with no shelf cut into the bow.I do think you could ever get those to fly well no matter how much weight you add up front.You might look at some .600 spine arrows or even CE Predator II in a .700 spine.For me I find aluminum some times work better for lightweight  bows not cut close to center.Maybe try aluminum in a 1716 or 1813.

my 47 lb self bow shoots 35-40spine woodies great with 125 grain target tip.
Larry

Thanks guys. I will stop by my local outdoor shop and ask some questions. I wanted to be armed with a little knowledge first. This is the place for it!

I agree that .300s are way overspined for your bow.  Unfortunately, unless someone at your local shop shoots a trad bow, they wont be of much help in selecting the right arrow spine for you. A .600 in carbon, maybe an 1816 or even 1716 in aluminum or 40-45# spine in wood should work for your bow if you draw about 28 inches.  Good luck.

Yeah I'd say you are overspined. The porposing indicates your knock point; if the arrow strikes with knock up then your knock point is too low, if it hits knock down your knock point is too high.

With spine, if your arrow hits nock left your arrow is too weak, if your arrow hits nock right your arrows are stiff or over-spined.

Here's a good guide to help you out

http://www.goldtip.com/arrowperformance.aspx?coid=16

If your arrow is porpoising, then your nock is not right.  I use a piece of masking tape as a temp. nock to figure out where it should be. Move it around until the arrow launches straight.  Shoot from farther to give you time to watch it fly.

Thanks guys. I picked up a pair of carbons with a 600 spine so I can give those a shot and get this thing tuned up!