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6br 103gr in 1:9 twist ?

Posted: Thu Mar 26, 2015 12:25 pm
by cameron22
Hi
Still very new to this shooting scene.

I just purchased a fly rifle/ f open in 6br.
It has a brand new barrel fitted and has shot well with the 95gr Berger vlds.

It's a 1:9 twist and was wanting to try 103gr copper heads or 105gr Berger vlds.

Will they stabalise in the 9 twist?
I have had mixed opinions on this.

I was thinking bit heavy projectiles will help in the wind.


Cheers
Cameron

Re: 6br 103gr in 1:9 twist ?

Posted: Thu Mar 26, 2015 3:07 pm
by williada
Hi Cameron,
The 1 in 9 will fall short on gyroscopic stability with the heavier pills. It could perform at 300 yards. It will fall away as distance increases. The lighter bullet can go a lot faster and so the wind has less time to affect it and matches the optimum gyroscopic stability formula. I always give grouping ability more preference to wind bucking ability. Draw up some wind tables matching the lighter pill and use them on the mound while you are learning them and I am sure you will beat guys and gals using heavier pills who can't read wind. David.

Re: 6br 103gr in 1:9 twist ?

Posted: Sun Mar 29, 2015 3:10 pm
by RDavies
Some friends and I have inadvertently tried to shoot 103s and 105s on a 9" and 10" twist. (they were meant to be 8" twist).
The 9" twist actually shot the 103s quite well at 900yds in mid summer.
I got 103s to shoot OK (not great) in my 10" twist in mid summer as well. (The 95s went OK in 10" twist in warm weather) As soon as the weather cooled down (air more dense) both rifles went TERRIBLE.
When the 9" twist 6BR went back to 95gn VLDs it shot MUCH flatter and more accurately than the 103s.
My main Dasher is actually an 8.3-8.5" twist and shoots the 95s more consistently than the 105s in winter.