Bullet RPM Per Inch Math Problem

[Tumbleweed]

Simple method: Muzzle velocity × 720 ÷ twist rate=RPM

Actual method: Muzzle velocity × 12/twist rate × 60 = RPM

Calculating simple rpm wasn't the issue. Revolutions per inch or foot at a specific distance and speed was. People a little better at math than me helped figure it out. Ha ha

 

[bigred1]

External ballistics be like this sometimes...

https://media1.tenor.com/images/e5875add5503b4bf2174c59f146b16d3/tenor.gif?itemid=15394332

I think I tried this after my first batch of home brew!

 

[264MHC]

I don't have much experience testing different twist rates on game but I would think faster twists cause better terminal performance simply because the bullets are more stressed and closer to coming unglued. When they hit an animal it would only make since that the more stressed bullet would expand more violently. I guess my theory doesn't really work for monos though so maybe the extra rotational velocity inside the animal does have something to do with it.

 

[squawberryman]

The media used the spinning buzz saw of police death to get rid of Black Talon ammo way back. It does make you wonder if bullet manufacturers actually take this into consideration, or if it's just rifle nuts that overthink things.

 

[Tiny Tim]

I don't have much experience testing different twist rates on game but I would think faster twists cause better terminal performance simply because the bullets are more stressed and closer to coming unglued. When they hit an animal it would only make since that the more stressed bullet would expand more violently. I guess my theory doesn't really work for monos though so maybe the extra rotational velocity inside the animal does have something to do with it.

Increased gyroscopic stability also contributes to the bullet staying on coarse as it penetrates through flesh without tumbling.

 

[264MHC]

Very Good point.