Welcome to GBO Cannons. We are glad to have you aboard.
From your post it appears that your cannon may not be appropriate for this forum. You did not give us enough information to clearly determine that.
For our board the cannon must replicate a cannon made before 1899. you will find our
Read and Heed! Board Rules post clearly defining what guns are allowed on our board.
We interpret the ATFE regulations to say breechloading cannons made prior to 1899 shooting ammunition no longer made in the U.S and not available in commercial channels is considered an antique and allowed to be discussed here.
That would mean for this board the chambering in your cannon would have to be a chambering of a type made prior to 1899.
If the gun is a replication of a pre1899 cannon and has been redisigned to shoot fixed ammo it is not allowed
The whole issue fixed ammunition will have to determined by ATFE. If you will provide us with a copy of a determination letter from ATF stating your gun and ammunition meets the definition of an antique we will allow discussion of your gun on our board.
The discussion of the interpretation ATF regulations on our board is always off limits. There is already to much bad information about ATF Regulations on the internet and we do not want to be the source of any additional. The only place you can get correct interperetations is from the ATFE.
So until you can show us that your gun replicates a pre 1899 gun and ammo, or you provide us with a copy of a letter from ATFE defining your gun as antique you can not post on hti s forum.
GBO does have an
exotic weapons discussion forum You should be able discuss post 1898 DD's there.