Velocity or BC
Which one to believe in?
High ballistic coefficient (BC) bullets are all the rage now days, and there’s some science to support their popularity. However, sometimes a lighter weight higher velocity bullet with a lower BC is a better option. But it seems like most hunters either don’t realize this fact or they ignore it. Let’s look at an example to see how a lower BC faster moving bullet can be a better option than a higher BC—and heavier—slower moving bullet.
Buck season opens here in West Virgina in a week and today I was zeroing a Proof Research Glacier Ti rifle in 25 Creedmoor. The only factory load for this cartridge suitable for big game hunting is the Hornady 128-grain ELD-X load, and that’s the load I was sighting in the rifle with. However, I got to thinking that when I’d ran the numbers for one of my handloads for the 25 Creedmoor, it might be a better option. (Since I’ve been working with this cartridge for a decade as my wildcat 2Fity-Hillbilly, I have a good bit of handload data for it.)
The supplied chart illustrates the external ballistics for both loads, but I probably ought to explain the chart a bit. The first thing you should know is that unless I know I’ll just be hunting in the woods, I zero all my big game rifles using the 1/3 second rule.
The 1/3 second rule tells you the theoretical distance at which you can hold dead on a six-inch target and not miss. You simply determine how far your bullet can travel in 1/3 of a second and then zero your rifle so the bullet impacts the target three-inches low at that distance. From the muzzle to that distance the bullet remains within three inches of your line of sight. To establish the data for this chart, a 1/3-second zero distance was used for each load. The 102 Controlled Chaos load has a 1/3-second distance of 300 yards, which would put the bullet’s path dead on at 256 yards. The ELD-X load has a 1/3-second distance of 280 yards, which puts the bullet’s path dead on at 237 yards.
Clearly, out to 300 yards the Controlled Chaos load shoots flatter. In fact, even though the bullet’s BC is substantially lower than the BC of the ELD-X bullet, because it can be pushed so much faster it shoots flatter at 500 yards too.
