weak spine problem ??

[silent sniper]

Hey guys I think I have a problem. I just ordered my first carbon shafts for my 55# bear grizzly. I ordered heritage 150 shafts. Well I bare shafted them and they shot weak to the right. Well I kept cutting them down and finally stopped when I couldn't go any shorter at 29". Than I fletched them and they twirled to the left in flight. After adjusting the nock point I finally got them close. Paper tuning showed a bullet hole with a slight right sided tear. So now they fly pretty decently. My concern is the fact that I have to use a 100 grain point to keep my spine stiff, and I'm afraid this will lead to inadequate penetration on deer. I can hit what I am aiming at but I'm only getting 3" of penetration in a hard foam target with Simmons sharks. Will my current set up work for deer or should I look more into the heritage 250 shafts and start all over ? Thanks SS

[Bear Heart]

I think those would work for deer but: that arrow is kind of light, be careful not to overdraw and cut your finger.

Are those the new lighter colored (simular to GT) 150 or the older dark colored ones? Personaly I would get some of the new 250s and save those for 3D

[m midd]

You could build your plate out and shoot a little heavier head

[MnFn]

I had a similar experience. I had some 150's for a bow that I sold. I tried to make them work for my 55# kota but I ran out of length before I got them shooting good.

I bought some 250's and added weight be using brass inserts and bingo. Just what I wanted. Mine are cut to 28.75"

[Fanto]

there are some things you can do.

1) add an internal footing, by glueing in a timber dowel , behing the point. this will stiffen the shaft a tiny bit, and also increase weight and FOC. Dr. Ashby reccomends a 7" dowel, sanded down a little from the centre to the back end, so that the glue only holds the front half. you should get 40 grains from this.

2) add an external aluminium footing. 2" gives another 20 grains, no spine reduction.

3) add a squirt of silicone at the nock

4) build out strikeplate

cheers