At a guess, some governmental entity is hassling an American Legion post over the cannon on their law. But to essay an answer to the question?
According to lexicographer and friend of many of the founders, the “right to bear arms” includes the right to possess and carry any weapon “‘charged with (gun)powder, and any appurtenances thereto.”
Cannon are certainly “charged with gunpowder,” so possession and carry is a protected right. so much is clear, but the right to “carry” that cannon is not.
In the case of the American Legion post, “Progressive” public servants consider a display of militaria to be “glorifying the military” and do their best to fore those displays out of public view. In 1969 ATF tried to seize a VFW post’s cannon, on grounds that the concrete could be chiseled out of the bore, rendering the Spanish American War relic work for the scrap yards cutting torch.
It didd not take long for a Congressman who was a member of the VFW to shut that down.