What was the purpose of the circular ring on “old” cannons right before the muzzle


I’m guessing it’s for structural reinforcement, but not all cannons seem to have it, and I’m having difficulty understanding how making a small ring which seems to be less than a cm thick extra would make enough of a difference to warrant adding it. Also, does it have a name?

EDIT: Image: https://imgur.com/5oGdoAm

In: Engineering

It is likely a muzzle brake that redirects part of the propellant backwards to reduce recoil.

Search for an image of “muzzle brake cannon” and look it that is what you were asking about. If not reply with an image of what you refer to if that is not the case.


From that pic, you can probably find the name. Most likely it is the muzzle moulding, which doesn’t really have a purpose aside from being the part right before where the muzzle is cut flat.

[This 1832 reference](https://books.google.com/books?id=xlJXAAAAYAAJ&q=swell+muzzle) has “the diameter of the swell at the muzzle is so proportioned in all to the respective base rings as to give a dispart of a degree.” This strongly suggests that sighting was at least part of the reason.