| OahuKaneohe |
| (.275 member) |
| 14/06/19 06:20 AM |
Re: John Rigby hammer under lever 450 BPE 3 1/4
|
Utilizing the Greenhill formula to obtain the optimum twist rate for the: length, diameter, velocity
and specific gravity (I used lead), gave 38.8 inch twist rate.
https://www.vcalc.com/wiki/AndrewBudd/Greenhill+Formula+for+Optimal+Rifling+Twist+Rate