Well the round looks like crossed rifles or muskets but I was hoping there may have been more details to it besides what the first fuzzy photo showed. I am still coming up blank but now that you have good photos of the marks on file, that is good to have in case you post the photos on some collectors forum or the like, if you get no joy here. They may be private proofs instead of official proofmarks of an established proof house. I am still looking but most online sites show proofs of commercial or military guns used since the middle of the 19th century or 20th. I was looking in a book that showed some 18th century marks but I did not see that one. Will keep my eyes open.