Maybe some others have observed this, so I was curious. I have been working up some different 9mm minor loads for my mpx. I decided to try some VV n320. The bullets are blue bullets 135gr TC and Berrys 135gr HBFP. I used the same primers, brass, charge weight and OAL. The chrono shows on average about 51 fps faster for the blue bullets. They are pretty much the same shape and weight. The Berrys are slightly larger in dia.
I tried this with another powder, CFE pistol and the results were the same.
Any ideas why the Blue Bullets would be faster?