Perhaps the 5-inch barrel has something to do with it. I'll post the rest of the test over in the ammo section so differences in velocities between the barrel lengths may be seen.

I was thinking the gray (silver?) box of Winchester was current. The white box dates from about 1980. The Remington 158 grain +P is late vintage. I've heard that the Remington stuff gives a little more velocity and it seems to be so.