Based on letter from ATF we have recieved, bowling ball mortars are no longer off limits on this board. See copy of the letter below.
Any discussion of making mortar tubes based on the Stokes design has been put off limits on this board. The Stokes is a post 1898 design and in our opinion does not meet ATF's definition of an antique or replica cannon.
The Three Inch Stokes MortarIf you can provide a letter from ATF saying that the muzzleloading version of the Stokes design is considered as meeting the antique muzzle loader design we will allow discussion after the letter is posted on this board. Please provide the Moderators with a copy of such letter and we will post on the board and open discussion.
We do this for several reasons. We don't want anyone to think that we here are saying that the making of a Stokes design is exempt as a an antique just because it muzzleloads, that is for ATF to say. We also don't want ATF setting up a data mine on this board to look for unintentional innocent violators.
If others say it's legal to make a muzzleloading Stokes style mortar, that's fine, they can defend their postion with ATF. We here will only deal with what is obvious to us as clearly being with in the definition.
Check here for additional information
This from the FAQ's ATF website.
http://www.atf.gov/firearms/faq/national-firearms-act-firearms.html#muzzleloading-cannonsAre muzzleloading cannons classified as destructive devices?
Generally, no. Muzzleloading cannons not capable of firing fixed ammunition and manufactured in or before 1898 and replicas thereof are antiques and not subject to the provisions of either the GCA or the nf. [26 U. S. C. 5845, 27 CFR 179.11]
PART 179--MACHINE GUNS, DESTRUCTIVE DEVICES, AND CERTAIN OTHER FIREARMS--Table of Contents
Subpart B--Definitions
Sec. 179.11 Meaning of terms.
...Antique firearm. Any firearm not designed or redesigned for using
rim fire or conventional center fire ignition with fixed ammunition and
manufactured in or before 1898 (including any matchlock, flintlock,
percussion cap, or similar type of ignition system or replica thereof,
whether actually manufactured before or after the year 1898) and also
any firearm using fixed ammunition manufactured in or before 1898, for
which ammunition is no longer manufactured in the United States and is
not readily available in the ordinary channels of commercial trade.