BLR 308win revisited

[xsn10s]

It is not about bullet weight - it is about bullet length. 180 grain Round Nose cup and core lead bullet is very different than a 175 grain vld style mono-metal. You will want run your bullet through a stabilizer calculator.

Yup I agree. Here's a screenshot using Berger's barrel twist calculator.

 

[med358-boise]

Yup I agree. Here's a screenshot using Berger's barrel twist calculator.

View attachment 664025

Exactly. Your example above is for the Hornady 180 grain Round Nose based on the bullet length (1.168) If you run the same calculation with the the Berger 180 ELite Hunter which has a length of 1.375 inches the SG = 1.24 which is "marginal stability" and dramatically lower than the SG for the same 180 grain weight round nose bullet.