Rifle Barrel date 1764 Marked AM

[Valleyfarmer]

Thank you for adding me to the forum. I am looking for some identification information. I technically don't have a "rifle" but the remains of one. I pulled this barrel out of the scrap iron pile when the family was preparing for my grandfather's auction sale back in 1972. It looked like a piece of  rusty pipe. I was 16 years old and hunting and firearms was a big interest at the time and luckily I realized it was a gun barrel! I dug into the pile and found a flint lock (and an old Belgian smoothbore 22 barrel too). That was the only parts I found. Being a kid I got some oil and a brass brush and started to clean the things. I was really surprised to see tha there were decorations and the date 1764 on the top of the barrel and the initials AM on the side. There are some other figures that are kind of corroded. I stuck a rod down the barrel and measured and discovered that the bore did not go down as far as it should. A little probing with a cleaning rod (luckily aluminum) revealed that the barrel was still loaded with buckshot! I have kept the barrel in the gun safe and the lock soaked in oil for all these years. Unfortunately  I couldn't ask my grandparents about it, but my grandmother's family, the Allens, came from Covington, NY and Addison VT area with connections to MA as well. Grandma and her sisters were members of the DAR so had some connection to the Revolutionary war times. I am wondering if the gun had been in her family and brought to eastern Iowa in the 1870s. The lock and the gun I am supposing were once one firearm? I finally have a home where I can have a "man cave" and I would like to display / restore /recreate something with these parts to hang on the wall but have no idea what the rifle should look like. So I have begun to do some investigating. Any assistance and information would be appreciated. I will post a few pictures and am interested to see what you all think. I have more pictures if needed as well. Thanks!

[Elnathan]

The lock is a Scandinavian snaplock.

[Shreckmeister]

You came to the right place.  Lots of knowledgeable guys here to help you.  Good luck.

[WESTbury]

There's a photo of a somewhat earlier version Swedish Snaplock per Moller's Vol. 1. page 44.