Most likely, your 777 holes had more velocity/energy -- resulting in the difference in the circle-edging.

When was the last ime you cleaned the trigger assembly & lock assembly? Use auto brake cleaner spray & gun oil with a soft toothbrush for the lock... light oil spray -- then a dry toothbrush & dry cloth dabbing for the trigger areas. Look for black paint missing on either assembly -- seeing shiny, silvery parts instead. That's a sign of wear. Also, when removing either, look for small wood chips from the stock which may signal binding. Hope this solves your problem.

P.S... Alky is rubbing alcohol. Buy a minimum of 70% that's usually shown on the front label. It'll usually say 50-70-90% somewhere on the front paper. Use it to remove all traces of oils in your bore prior to shooting. Use it to remove water/moisture after cleaning the bore with soap & water treatments many ml shooters use... especially with sidelocks.