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
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
2nd Amendment of the U.S. Constitution. - "A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."
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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.....
BP | Bronze Point | IMR | Improved Military Rifle | PTD | Pointed |
BR | Bench Rest | M | Magnum | RN | Round Nose |
BT | Boat Tail | PL | Power-Lokt | SP | Soft Point |
C | Compressed Charge | PR | Primer | SPCL | Soft Point "Core-Lokt" |
HP | Hollow Point | PSPCL | Pointed Soft Point "Core Lokt" | C.O.L. | Cartridge Overall Length |
PSP | Pointed Soft Point | Spz | Spitzer Point | SBT | Spitzer Boat Tail |
LRN | Lead Round Nose | LWC | Lead Wad Cutter | LSWC | Lead Semi Wad Cutter |
GC | Gas Check |