OK, going back in time, a 1980s era Hornady manual does give 5.2 gr of 231 as a max load. Added edit: listed COAL is 1.060 in.

A 1999 Winchester manual lists a start load of 4.2 gr and a max of 4.5 gr with a 124 gr RNFMJ with a pressure of 32,700 psi. However, I've found the Winchester manual to be exceedingly cautious, probably due to really tight chambers and barrel tolerances.

However, current Hodgdon data from their website is 3.9 gr start, 4.4 gr max with a listed pressure of 31,900 psi. Bullet appears to be a plated bullet which would help account for the lower pressures. Again, this would be in a pressure barrel in a universal receiver.

Seems like 124 gr bullet & 231 isn't a real good match in 9 mm.