I decided to change brass on one of my 300Win Mag loads and see what the difference would turn out to be when using my 165gr Sierra HPBT. I was using Winchester brass but the last bag I bought was not a good batch and I was disappointed in the quality. So I bought some Remington brass. I really like this brass. So I did my usual annal retentive stuff every time I load rounds. I used the same load chain 165gr HPBT, CCI250 primers, IMR4350 except for the brass. With the Winchester the velocities were 3218fps and with the Remington the velocities were 3182fps. The accuracy was pretty much the same. I did have less expansion at the base of the bullet using Remington brass.
These two five shot groups are all but identical in size. The group shot with the Remington brass was shot with the first and last round from a completely cooled barrel. Folks kept coming up and talking to me at the range and so my intervals between shots using the Remington brass were not consistent like when I shot the five shot group using the Winchester brass.
165gr Sierra HPBT Game King, five shot group Winchester Brass, CCI250 primers and IMR4350, moving 3182fps
165gr Sierra HPBT Game King, five shot group Remington Brass, CCI250 primers and IMR4350, moving 3182fps Extreme Spread 11.75fps Deviation was 5.47 much better than the Win brass