If my arrows usually fly beautifully, but occasionally wobble around a bit, is the problem most likely a form issue or a spine issue?

I shoot a Bob Lee Signature take down (60# @ 28").  My arrows are 30 inch aluminum 2117s with 200 gr. points.  My draw length is about 29 inches.  

Stu's calculator and all the charts say I'm way under spined, but the 2117s usually fly great.

My thinking is that if my arrows are under spined, they should fly badly all the time - so the wobbly ones must be me.

looking at the numbers, I would say that you are underspined.  With a good release and solid bow arm, the fletching may be able to straighten things up before you can see it.  Any errors in form will exagerate the poor flight.  Try dropping down in point weight and see if your arrow flight improves.  This should answer your question.

My opinion is that you're thinking right.  If the arrows are wrong, then you need to look into fixing them...BUT they should fly *wrong* all the time assuming they weigh and spine the same (relatively) and are straight.

I suspect a lot of successful people in "shooting sports" of all kinds do, and use, the wrong stuff...but they do it wrong *consistently*.

We don't worry about "good form" for the sake of "good form"...we worry about "good form" 'cause it makes consistency easier.

YMMV

how do they fly with no fletch? I'm by no means an expert on this stuff although I have shot traditional bows for quite a few yrs. But this last yr I have been learning a ton. I was using stu's calculator too and it always seemed the setups that shot the best were underspined for my 53@28 bow. Then one day I got a hankerin to shoot a 340 spined carbon bare shaft. By all rights this arrow is way to stiff, but lo and behold that arrow flies straight as far as I dare shoot it, 40 yards. I mean it flies like it has feathers on it, perfectly straight and half the time the arrow hits the bullseye and the other times I'm just a little off. Stu's calculator says I'm even. I can come up with an even setup with a 400 or 500 spine but the bare shaft turns in midflight nock left, which I suppose is to weak. The point is, I bet your to weak. Pick up one 340 spined gamegetter or carbon arrow and give it a whirl. I bet you'll be surprised.

i shoot almost the exact same setup though i little more draw and draw weight they fly great if my form is true. yes i know stews shows light as it does for my2216's but that happens with more foc. try the 2216's but i think you just need to bern in the form at blank/blind bale as do most of us.lmk how it goes.  

drop point weight and see how they fly

If you spine is weak and your form is perfect you will get good arrow flight.  A good test is to put a wide 200 grain broadhead on the shaft and shoot the broadheads and field points and see if they group.  I am willing to bet they won't.  If they don't group together you may  want to consider changing shafts.  A properly tuned and spined set of arrows will compensate for the occasional form error with you shafts on the edge of spine range or out of it even minor form errors are magnified.  It always amazes me how much even a little bit of fletching improves arrow flight.

Thanks everyone!  Great advice.  I'll try different point weights this afternoon and see what happens.

Stu's calculator says I'll be just about right on with 125 gr. points, so if my arrows still wobble some with the lighter points, it's me, not the spine - right?

I also think you're underspined, but should be very close with 125 gr points I would think.  If they still wobble with the lighter points you might check your brace height also.