According to what I found in Pegler's book Powder & Ball Small arms---there are a few pages dedicated to a big pistol with English lock.It effectively is an fairly standard flintlock with the lockplate being rounded similar to a wheelock. But the frizzen and the pan work as a standard flintlock would. The lock exterior looks very different from standard more modern locks. The **** and flint are very beefy, the frizzen spring looks familiar though the book says that the pan and frizzen were a one piece forging??? but there are other gee-gaws on the lock that are a mystery to me. I should imagine Master Robin might be more knowledgeable on this matter---however I thought I could share something from this book. :hmm: