I choose to believe what Parker said
Parker Brothers 1893 Catalog
“Our guns are bored on the latest improved system for shooting Nitros, or Smokeless Powder, and all our guns are tested with some one of the most approved makes, and a tag accompanies each gun, giving the results of such a (pattern) test.”
1902 Sears catalog No. 112
“THE PARKER GUNS: ALL ARE BORED FOR NITRO OR BLACK POWDER”
More mythology, and myth busting here
https://docs.google.com/document/d/1...hIiY62Hx4/edit