The effective g_A in the pf-shell

We have calculated the Gamow-Teller matrix elements of 64 decays of nuclei in the mass range A=41--50. In all the cases the valence space of the full pf-shell is used. Agreement with the experimental results demands the introduction of an average quenching factor, q=0.744 +/- 0.015, slightly smaller but statistically compatible with the $sd$-shell value, thus indicating that the present number is close to the limit for large A.