Is there any kind of formula for calculating the best twist rate? Caliber, boolit weight, load, ft/sec, barrel length? Or is it just what has been known to preform well?
Thanks
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Is there any kind of formula for calculating the best twist rate? Caliber, boolit weight, load, ft/sec, barrel length? Or is it just what has been known to preform well?
Thanks
Greg,
try Greenhill's ready made formula here :
https://www.vcalc.com/wiki/AndrewBud...ing+Twist+Rate
I've not used that link but the following Wiki link has the formula if you want to do it yourself:
https://en.wikipedia.org/wiki/Alfred_George_Greenhill
....interesting most formulae such as Greenhill's rely on a constant and are limited to velocities sub 2400fps - I prefer to use Millers formula (based on Greenhills') that accounts for a greater number of variables including copper jacketed etc...
His formula called the Miller Twist Rule can be found here
https://en.wikipedia.org/wiki/Miller_twist_rule
Hope they help.....