I've verified that the information supplied by kcwheel is correct:
F A 4 06 & with punch crimps = CN jacketed bullet, .528" rim, .472" head, .918" case length, .451" bullet at mouth, 1.299" OAL & 350.0 grains total weight.

It seems clear that this is indeed the .45 "Experimental" (or Frankford, or S&W Special) revolver round manufactured by FA for test use in the S&W and Colt revolvers included in the 1907 pistol trials. It would seem the differences in the round from the old original .45 Government (Schofield, M1877) round are in the use of smokeless powder instead of black powder, a slightly shorter case (which would be more efficient with smokeless powder), and a jacketed bullet rather than lead. I would not be surprised that extraction problems while using this cartridge were experienced in the trials, leading to the later adoption of the Model 1909 cartridge having a larger rim and a longer case.