"Keith Willshaw" wrote in message
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"vincent Brannigan" wrote in message
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Keith Willshaw wrote:


The napoleon was a smoothbore and its production involved
much less boring and turning than a rifle

The true comparison is between an iron
smoothbore and a napoleon. The columbiads
while admittedly larger than the napoleons
were also smoothbores

I agree that rifling adds to cost, but not that much.

I rather disagree.

The cost of boring
(drill the main center tube) and turnign (trunnions) is the same.

However the machinery required to cut rifling in a cannon
bore is of an entirely different order from the simple boring
process adopted for a smoothbore. There's a good reason
why rifled cannon didnt appear on the battlefield before
the 1850's and the rise of the machine tool is a large part of it.
It wasnt until 1841 that the first standardised screw threads
were introduced by Whitworth for example.



I'll chime in here being a Gun enthuist as well as knowing a thing or two
about the rifling process.

to rifle the barrel is actually a 3 step process, Bore, Ream and rifle.
you start with a single point rifle drill to drill the basic hole this is
the most dificult part drilling a stright hole.
then you ream it easist part to the finished Lands demension.
Then you rifle. The rifling process takes about 4-5x the amount of time to
Bore or ream.
The rifle cutter will cut one grove per pass it then indexs and cuts another
and it cuts a very little bit of metal. ( in 0.00001") per pass.
so to rifle a barrel takes literally thousounds of repeated passes. Even on
a fully automated machine it takes a long time.

Jim