The most recent article I am aware of was in HANDLOADER magazine five or more years ago; another in either GUN DIGEST or HANDLOADERS DIGEST along about the same time. Kent Bellah, well-known gunwriter in the '50s & 60s was an advocate of the various Lakeville Arms products and he wrote about all of them. Bellah, from Saint Jo, Tx died in 1966. One problem with the zinc washers was the loose and non-uniform dimensions to which they were cut and varying bore sizes. In theory, they were supposed to have a "scraping action" and "Sherrardized" (coated) the bore as inventor Jim Harvey called it. I've used the washers with some success.