90 gr. Swift Scirocco

[Greg Duerr]

Ive heard that its hard to get the 90gr. Scirocco to shoot out of a standard 1x10 twist in the .243....................What about the 1x9?

For those who shoot the 90gr. Scirocco what works for you..................and how does the bullet perform.?

G

 

[squeezenhope]

Going the wrong direction. IF the 90 grain will not stabilize at 1in10 it would be highly unlikely for it to improve by going to a faster twist.

 

[Greg Duerr]

So I should go to a 1x12 or 1x14?????? I think your heading in the wrong direction

 

[squeezenhope]

That is exactly what I am saying, but I think 1x12 would be plenty slow for a 90 grain 6mm bullet. If you think I am going the wrong way you might want to research the evolution of twist used by Remington for the .244/6mm.

 

[Greg Duerr]

I heard that the standard .243 twist is 1x91/2, I think Berger sugjests a 1x9 for their 95gr and a 1x8 for their 105 the long Scirocco would need a faster twist than the 1x10 if it wont shoot in the 1x10 my rifle has a 1x9 twist and was told by Swift that the 90gr. Scirocco shoots best in a faster twist rate.........most guys I have talked to could not get them to shoot well in their standard factory barrels....................

 

[TJAY]

Rule of thumb.

Longer bullet needs faster twist rate.

Lighter bullet=shorter bullet, heavy bullet=longer bullet

90 gr Swift Scirocco is a long bullet for its calibre

 

[squeezenhope]

AGREED. But this post started out asking about 90 grain bullets, but somehow has morphed to 105's??? Moving on.

 

[Beng]

This website says the bullet is 1.132" in length.
Using the jbm stability calculator, I get a minimum twist rate of 8.5" per revolution at sea level for 3000f/s mv.
The Applied Ballistics point mass solver agrees.

 

[angus-5024]

"Going the wrong direction. IF the 90 grain will not stabilize at 1in10 it would be highly unlikely for it to improve by going to a faster twist."

heavier, longer bullets using a slower twist ehh? (im Canadian, excuse the ehh).
Well, i think that you should chamber a .243 with a 1-12 or 1-14 tube and let us know how it works for you with the 90 grainers.

berger recomends a 1-9 twist minimum for their 95's. got a box of em in my hands. A 1-10 may stabilize the 90's, but it'll hit or miss. A 1-9 will do the trick though.