Since the late 80s. This is one of the KGP series, which supplanted the all cast ZAMAK earlier examples, the La, Ep, and Et-22s from the 60s. The grip frame on the later ones remained cast zinc alloy. Clean and lube the thing before you shoot; a drop or three of lube into the mag sometimes helps as well. This series generally functions better than the early pot metal versions, so that's good. Price range is around $400, give or take for condition. One eccentricity displayed is the tendency to throw their extractors. There are 2 left on eBay, and I suggest a spare. At $14.99, a bargain for a difficult part to find. The tiny extractor spring and its guide/plunger may prove more of a challenge, unless Bob's Gun Parts still has some. Parts come and go at the online auction and classifieds sites, but if you are patient with your Erma needs, I think you'll succeed.