Sierra 2156 form factor

[sparker]

Using the dimensions represented in Litz's first book, I plugged them into the form factor equation found in the appendix. This yielded a form factor value of .985 which is slightly smaller than the .988 value given for the Berger Fullbore bullet. The calculated value is in very good agreement with the Fullbore bullet value as the two bullets, both in dimensions as well as ogive shape are nearly identical. I'm very curious as to where the 1.018 value for the form factor for the 2156 bullet came from. Was this simply a testing anomaly?


Scott Parker

 

[sparker]

Crickets...

 

[dcali]

The equation in the back is rough at best - it's just a line fit based on trends. I'd guess that the difference in measured values is attributable to testing variation, and the close match of the calculation to the Fullbore bullet is just a coincidence.