I made a coil spring mule ear lock when I was a teenager. It worked, but I never put it on a rifle. I had earlier make a coil spring back action lock that worked just fine on a halfstock rifle. (That was before I ever saw a TC coil spring lock.) I lost track of the mule ear through years, Vietnam, a divorce, and other stuff. A year or so ago my daughter gave me an old jar she had saved from my exwife's house, with some old
junk in it, including most of the mule ear lock. I used to make the tumblers out of high-strength bolt heads. (Travesty, I now know, but in those days, we had little money, and a lot of time.) I am still not great at making flat springs.