When the NYPD made those Speer 135gr .38 Special +P rounds standard issue they were also standard issue for those officers who were still carrying service revolvers with 4" barrels.
The only problem you would run into using a bullet designed to expand reliable at the lower velocities associated with a short barrel is lower penetration depths. If you add 200 fps the bullet will expand sooner and possibly prevent the bullet from penetrating to it's tested distances. In any case, they are perfectly safe.