I've adjusted the nocking point on the Osage flight bow to remove the porpoising of the arrows. I initially thought it needed to come down, but as I slowly lowered it I found the arrows were still hitting the boss point down at 10 yards, so I went back to how it was and up a whisker, they are hitting straight now.
I wasn't taking it to full draw as I was a bit scared of smashing the comparatively delicate flight arrows (it's happened before). These all fly remarkably straight and hopefully that will help getting a good distance.
I've made 2 more, one is the 5/16" cedar shaft but with much more taper at the back. The other is 9/32" pine barrelled, I was worried it might be too fragile, but they fly nicely from this bow.
Matching spine to bow really depends on the bow as well as the arrow, if there is little flexing then you can get away with a smaller diameter (and correspondingly weaker spine) for better aerodynamics. It's really a matter of, as light and skinny as you dare!
I had one bloke on a forum calling me an idiot because I said you could go to light spine from a warbow as long as you have a light point. I left the forum as he wasn't even reading my explanations or indulging in rational argument. Some people equate bow poundage to required spine as if they are somehow linked... it's ok as a guide but you have to remember a short 75# bow with short draw can shoot faster and further than a warbow, and with the short draw the arrow is accelerating much faster.
I'm just back from shooting. 4 arrows shot then measured, repeated this 3 times.
I got a new PB with one arrow, but only by 2 yards (309yards, I was hoping for 310 at least) mind there was more cross wind than tail wind and the weather is dull and heavy.
I'll give the results below, they are pretty random, so I've done weight, max distance and average distance for each arrow.
In weight order, lightest first.
231gn 294 yards, 280yd average
262gn 289 yards, 287yd average
291gn 309 yards, 275yd average
326gn 281 yards, 276yd average
It shows how hard it is to draw conclusions, generally the lighter arrows went further, but the actual longest shot was with the 291gn arrow.
Now it would have been interesting to have shot say 10 times with each, but it would have been a lot of walking! It just needs that elusive really clean loose to add 20 yards to a shot.
Certainly the heaviest arrow was a poor performer, so I may re-work that one.
Some of the arrow flight was nice and clean, but there was a waggle on some. The arrow pass is showing some wear marks near the belly of the bow, I might remove the leather and relieve the arrow pass a tad to put the wear point a bit nearer the centre or back. Or does that just show I'm getting the arrow point well back at loose? I'll have to take a close look at how the arrow sits on it at brace, I don't want to rush at it and spoil it. Here's a pic of the arrow on there at brace, tends to confirm it needs a little adjustment.
Not sure if I'll get much more flight shooting this year, the grass is getting a tad longer again.
One thing I noticed was that I couldn't see the arrows in the ground at all until I was past them and looked back or across at them, then they showed up pretty well.
Update:- Arrow 4 has been substantially reduced at the nock end and is now 303 grains (from 326). The other arrows have had the nocks slimmed and adjusted as some were a bit tight on the string. They've all been sanded and waxed. It will be nice to give 'em another go if we get a good day for it. The arrow pass has been adjusted a tad, the leather peeled back nicely as it was only stuck with UHU glue. I tested one arrow at near full draw and it stuck in the boss good and straight from 10 yards.
One could possibly argue that the results merely prove that it's random, luck or whatever and there's no point trying to fiddle and fettle the bow or arrows. I'd argue that tuning it all up is an attmpt to maximise the chance of that elusive clean shot.