Everyone I know that is shooting PPC using S.A.9mm types. With what you describe on the RO sounds like "soft" material. Should not have loosened up in that short of time. Something not right. Depends on loads too that are going thru it. Shooting a steady diet of defense hot loads will definitely loosen um up. 9mils by nature maybe a little sharper recoil than a .45, and maybe even shoot softer, again depending on loads. Some don't like a load unless it leaves a small mushroom cloud and recoils out of their hands and shoot them for practice. Dirty Harry syndrome.