Need a little help fellas...I recently picked up a Bear Grizzly (45@28), but my draw is 27 inches.  I'm shooting 29 inch goldtip 35/55 with 100 grain brass inserts and 125 grain tips.  I'm getting some fish tailing arrow flight.  I also tried 100 grain tips, but did not see any improvement.  I'm using the Fred Bear hair for a rest.  I've tried different nock points, but haven't figured it out.  Do you think it is a spine issue?  I guess its possible it could be a release/form issue, but I'm shooting my Mojostik fine.

May need heavier point...

Generally side to side is brace up and down is nock. Try raising your brace height.

will do.  Brace is at 8 1/4 right now

My grizzly is at that also.50@28. 30 inch gt 3555arrow, 225 up front.

Increase to 250 up front. You can always decrease but it's better to start heavy.

Do you have a strike plate on the sight window?  If so try a thicker one.

1535's would be a better shaft choice. If you are going to stick with 3555's I would remove to brass inserts and put the standards in and increase the point weight to 200. Those inserts act as 1.5 inches of footing and stiffen the shaft.

the strike plate is the leather one that came on the bow from the factory

A small piece of peel and stick velcro on the strike plate like Mike suggested might help a lot.

Try a 125gr. point, decrease the spine. I shoot a 55# Bear Kodiak Magnum with a 500gr. arrow and a 125gr. point and it hits spot on, I've also got a 50gr. brass insert so effectively I'm shooting 175gr. up front. Although, your arrows could be underspine? Check out Stu's calculator and enter your values for the bow you are shooting, the arrow you are using and see what you get. It's priceless info.
Here's the link.
 http://heilakka.com/stumiller/  
Play with it a little bit and you will understand what I'm talking about. Hope this helps.
Chris

the spine is perfecf according to stu miller with the 125gr.

i think the problem is something else like nock fit too tight

also i use 5575s with 225 tips from a 55lb martin similar to the kodiak, perfect flight

The best way I've found to figure that out is to bare shaft tune them (if you haven't already). I'll take the arrows that I think should be in the right spine category, add the tip I want on a full length shaft, then shoot them with no feathers at 5 or 10 yards. If they tail to the right, they're too stiff, so try adding more point weight. If they tail left, they're too weak. Cut them down, starting a half inch at a time from the nock end, and repeat. you'll see them get closer to straight. When you're getting close, only take 1/4" off at a time. If they're cut down as far as you can get them and still spine weak, try reducing point weight. (this doesn't seen to have as much effect on super stiff arrows). If it still spines weak, then you need to get a stiffer spined arrow and try again. Once I learned how to do this, it DRAMATICALLY improved my shooting. Charts only do so much good, there are several variables that they can't really account for, and self tuning them is the way to go in my opinion.

I think you have too much weight up front, I have a very similar set up and I shoot GT3555 cut to 29 1/8 with 50 gr brass inserts and 145 gr point

after re-reading my comment, I was a little vague on a couple things. As you trim and shoot your arrows, they should gradually straitghten out to the point where they are sticking straight out of the target and hitting where you're aiming. The goal is to get them flying perfectly with no fletching, that is a properly tuned arrow. I've found that even well-under spined arrows can seem to fly perfectly with fletching, because it corrects them, but they are much less forgiving than arrows that are tuned properly. I would also experiment with your brace height, that can make a big difference too. You can change that by twisting (to shorten string) or untwisting (to lengthen string). Good luck!

QuoteOriginally posted by pitbull:
1535's would be a better shaft choice. If you are going to stick with 3555's I would remove to brass inserts and put the standards in and increase the point weight to 200. Those inserts act as 1.5 inches of footing and stiffen the shaft.

X2!

bare shafts are hitting tail right at 10 and 20 yards.  I will up the tip weight.  I also ordered a dozen of the 15/35 goldtips from bigjim to play with

Try going higher in point weight. I think you are still a bit over spined. The 3555's are a 400 spine shaft if I'm correct. I get perfect flight from 400 spine shafts cut to 29.5 " with 275 grains up front from a 55# center cut longbow. If you would like to learn about tuning the best article I have ever read is by O.L. Adcock called bare shaft planing which involves tuning based on shooting groups of bare shafts and fletched arrows the method can be found at  http://www.acsbows.com/  under their knowledge base tuning section.

I think 35-55's are 500.  the 15-35's are 600.