Straight from Higginson last week:
The only data we compiled for the WC-735 is for the 223 Remington or 5.56mm NATO round. It goes as follows:
50 gr. Hdy V-Max C.O.L. 2.250" 25.2gr. 3408fps @ 53,000PSI
55 gr. Hdy V-Max C.O.L. 2.250" 24.0gr. 3212fps @ 49,500PSI
55 gr. Hdy V-Max C.O.L. 2.250" 24.3gr. 3253fps @ 51,700PS
55 gr. Hdy V-Max C.O.L. 2.250" 24.9gr. 3302fps @ 53,200PSI
62gr. SPR FMJBT C.O.L. 2.250" 23.3gr. 3062fps @ 53,800PSI