H.L.A. Co would be my guess with the way the "O" was written after the C so I Googled that and got a hit for Henry Leigh Arms Company. Scrolled down and saw this web page.....
http://www.dixiegunworks.com/pdf_dat...e33477bc698ef7
Hope that helps.... I love old shotguns and own several myself but it's not like I knew anything about yours. I just happen to spend about three quarters of my day doing research work, yeah, they pay me to google stuff
