Corn-Picker
Member
I ran some numbers for multiple bullets from cartridges based on the same case; i.e. 260/7mm-08/308 or 270/30-06. To make a long story short, inside of 400 yards, and especially inside of 300 yards (my max range), the 30 caliber option always seemed better (more velocity, more energy, less drop, and less drift). Looking at the data, it seems like the performance of the smaller caliber can always be exceeded by a light for caliber bullet in the 308/30-06. A 110 grain 7mm bullet is slicker than a 110 grain 30 caliber bullet, but the low BC of the 30 caliber bullet is more than offset for by the increased muzzle velocity, so it still carries more energy and drops less inside of 400 yards .
The only way that the smaller calibers won out is if ranges were over 400 yards or wind speed exceeded 10-15 mph. As a sanity check, I did a brief check of some larger calibers (e.g. 358 Winchester), and in that case the lower BC of a light for caliber bullet did result in worse drop/drift performance at 300 yards.
Maybe this is common knowledge, but I found the math interesting. It reaffirmed my suspicion that my next rifle will be chambered in 308/30-06. I guess you could make a sectional density argument for the smaller bullets, but I use copper bullets exclusively and have never had insufficient penetration even with light for caliber bullets.
The only way that the smaller calibers won out is if ranges were over 400 yards or wind speed exceeded 10-15 mph. As a sanity check, I did a brief check of some larger calibers (e.g. 358 Winchester), and in that case the lower BC of a light for caliber bullet did result in worse drop/drift performance at 300 yards.
Maybe this is common knowledge, but I found the math interesting. It reaffirmed my suspicion that my next rifle will be chambered in 308/30-06. I guess you could make a sectional density argument for the smaller bullets, but I use copper bullets exclusively and have never had insufficient penetration even with light for caliber bullets.