twist rate formula

[rembolt]

Hi guys can someone give me the formula needed to determine the twist rate for a peticular weight of bullet.thank inadvance.

 

[Brutus]

Google, "Greenhill formula". The Mountain Moulds website calculator may be the top pick IF you can find the matching barrel twist, as a pick option, on the pulldown tab.

 

[RePete]

Look here.

http://en.wikipedia.org/wiki/Rifling

 

[rembolt]

thanks guys thats what i was searshing for.

 

[Lefty Dick]

So ya post on two sites and got the exact same answers.

2 links and one suggestion to use google, each.

See a trend.

www.google.ca

 

[rembolt]

ya I did was it money out of your pocket.i pay my internet bill so i use it as i like .thanks ####

 

[RePete]

ya I did was it money out of your pocket.i pay my internet bill so i use it as i like .thanks ####

Problem is that you didn't.

 

[bearhunter]

Good rule of thumb, " When over all bullet length is 2-2 1/2 x bullet diameter one turn in 15in is sufficient, 2 1/2 to 3 1/4 x bullet diameter one turn in 12in is ok, when 3 1/4 to 4 1/4 x bullet diameter 1 turn in 10 is ok, when 4 1/2+ x bullet diameter 1 turn in 8 is usually sufficient. For extremely long bullets 6 1/2 to 7 1/2 turns may be required"

This is just a general rule of thumb and fits the profiles of most barrels that are commercially available. It works well.