What is the difference…

Thanks everyone.

I can see how the definition could include cannon as something that can´t be hand held. (Not that you´d want to hang onto a 50 caliber!)

I would say, as a rough guesstimate anything above .50 Cal. (12.75mm) would be a cannon shell.

Just my humble personal opinion.

The definitive answer (as far as the period up to 1932 is concerned) is probably contained in the Williams/Gustin book advertised on this web site:
http://users.skynet.be/Emmanuel.Gustin/volume2/
Please note that I have no connection with the authors and publishers, so I hope this is not deemed advertising!

The answer is ‘blurred’!

It used to be as PL said; however, machine guns quite quickly acquired various types of rounds in air warfare – W.W.I had ‘De Wilde’ incendury ammunition, tracer etc, all from .303in guns. Larger calibre weapons (usually ‘cannon’) always had various types of round, including explosive. Tony Williams, a regular here posted some answers on the thread aluded to above. I’m sure his website (someone want to look? I’m no Dialup…) will clarify.

Cheers!

Yes I believe there was a thread a while back and it was the calibre, knowing me I am wrong though.

Suggesting! I am no armourer, I don’t like things that go “bang”!

Ah.

I like things that go bang very much, but not when they hurt people!

Suggesting! I am no armourer, I don’t like things that go “bang”!

Surely a cannon fires shells that explode on impact, whereas a gun fires lumps of lead!

Are you asking or telling?

Surely a cannon fires shells that explode on impact, whereas a gun fires lumps of lead!

Isn’t it just the calibre? Above a certain barrel size a maching gun becomes a cannon; I think that’s right.