Important Discovery. The Zastava M83/93 revolver factory hammer spring is the same outside diameter and the same spring wire diameter as a 1911 hammer spring with one less winding. This is compared to a Wolff 20 pound hammer spring that I installed in the Zastava. . It reduced the tension more than 10%. .38 and .357 primers fire double action with no problems so far. It is still a heavy trigger pull but much better than it was. Solid firing pin hit marks. I'm next going to try a 18 pound spring in it. Tom G.