High BC copper bullets?

[DagOtto]

Thanks Bluefish and Madcalfe.
Have updated with your additions plus cutting edge extended range.
Those Cayuga's have some bad-ass BCs if they are accurate!

 

[DagOtto]

In playing around with developing the ideal rifle and hand loads for hunting with copper bullets, I took a different look at BC. I started with the ideal impact velocity of 2200fps which seems to be the recommended "actual" effective impact velocity for many copper bullets. I set that 2200 fps goal for 400 yards which will allow me to shoot to 400 with a high level of confidence that bullet performance and wounding will be ideal.

Then, I worked backwards to what my Muzzle Velocity needs to be with various bullets of difference BC's in order to hit that goal of 2200fps at 400 yards.

I was pretty surprised that the required muzzle velocity to achieve my goals varies by a giant 400 feet per second between the "worst" BC of .4 and the best of .65. So just by picking bullets with the higher BC's you can make a velocity improvement that is equivalent to switching from a .308 WIN to a .300 Win Mag.

Clearly, for copper bullets that require fast impact speeds, BC matters a lot, even when looking at 400 or 500 yard max. shooting distance.

I am also embarrassed to admit that I had never realized that bullets of completely different calibers with completely different weights will behave identically if their BC's are the same. For example: a 260 grain .338 bullet with a BC of .450 and a 120 grain .243 bullet with the same .450 BC, when fired at the same muzzle velocity, will have the same drop and wind drift at all distances.... weird.



shoo

 

[sz28]

I killed a bull last December using the 125gr Maximus. Bullet worked as expected shedding petals with the base continuing on. I was shooting uphill from 280yds. Bullet entered, passed through the lungs and stopped under the hide on the opposite side. Impact velocity should have been around 2250fps. As the petals shed they caused quite a bit of additional damage, including one petal that traveled through to the spine, causing the bull to drop instantly and tumble. Unfortunately I forgot to take autopsy pics. Overall the bullet worked as the manufacturer described and BC was fairly accurate out to 500yds in my rifle.