The standard 40X trigger was a Walker trigger but usually had an external weight of pull screw. The 2 Oz. (three lever) trigger is also a Walker trigger and Mike Walker designed the modifications made to the standard trigger to produce the 2 oz. trigger. Many of the 2 oz triggers sold on 40X rifles were made by Hart but were also really just conversions of the standard trigger. In the '70's into the early eighties, it was common for gunsmiths to convert 700 or 40X triggers to 3 lever triggers following Walker's instructions. I know Dennis Sorenson, Nobby Uno, and I did these and I'm sure there were others as well. By the mid-eighties most everyone simply bought triggers from Canjar and, later on, Jewel. I still have a couple of conversions, a couple of Harts, and three or four Canjars. All good triggers.