The B6-6W I flew was in an Alpha...and it took it to over 940 feet! Granted, we were starting at 8000 feet MSL, but still....that's crazy height for a B motor. The very same model, with the same type of altimeter in it, has done 630 feet twice on an Estes B6-4 when launched from near sea level and 20 feet or so higher on a Chinese Quest B6-4.To be fair I should fly it on an Estes B6-6 here.
The B6-4W I flew was in my currently active Nova Payloader. It went to 465 feet. Here near sea level on Estes B6-4s typical flights of that model are in the ~275 foot range.