Distintive swell in the muzzle

[john pike]

i was reading about carronades
and there was a sentance,

they often had a distincive swell in the muzzle that made them louder.

can someone here who knows cannons,
 do a "for idiots"
explination of this?


johnp

[Cat Whisperer]

The real reason for a swell at the end of the muzzle is to provice added metal at the end - to reinforce the muzzle.  It is a weak point - there is no supporting metal infront, therefor more is added by going larger in diameter.

Louder - fiction.  I would suspect that whoever wrote that was drinking too many beers when he took physics.

The swell in the muzzle also looks good.

[GGaskill]

'Tis my understanding that muzzle swell was an early form of psychological warfare, used to make the opposing forces believe a gun was larger than it really was.  It became traditional and only disappeared in the final designs of muzzleloading artillery when conservation of materials became important during wartime.  Even the M1857 Napoleon had a muzzle swell.  The Confederate equivalent did not to save material.

[john pike]

'Tis my understanding that muzzle swell was an early form of psychological warfare, used to make the opposing forces believe a gun was larger than it really was.  It became traditional and only disappeared in the final designs of muzzleloading artillery when conservation of materials became important during wartime.  Even the M1857 Napoleon had a muzzle swell.  The Confederate equivalent did not to save material.

thank you
i learned something,
yu gotta love this group,
johnp

[Cat Whisperer]

'Tis my understanding that muzzle swell was an early form of psychological warfare, used to make the opposing forces believe a gun was larger than it really was.  It became traditional and only disappeared in the final designs of muzzleloading artillery when conservation of materials became important during wartime.  Even the M1857 Napoleon had a muzzle swell.  The Confederate equivalent did not to save material.

I would like to see a credible reference that mentions the purpose of the swell being psychological warfare.  It may indeed have had that effect, if one could even see it at the thousand or so yards away.

But the primary use of the swell is reinforcement.  There are numerous references to the swell (and other enlargements) as reinforcements; as well as the fact that the swell is one of two methods of reinforcing the muzzle (which is one of the weaker areas in the barrel).  The other method is to rebate the muzzle, giving more metal out front to reinforce it.

For example, current US artillery pieces are limited to 4,000 rounds at max charge.  It is common practice (each round is logged and the max-charge equivalent # of rounds is calculated) to check the muzzle for cracks as the 4,000 round mark is approached.  I've talked to several artillery men that have found cracks that showed up within the last 10 or so rounds before the 4,000 mark.

Further, the swell has not disappeared entirely, as it has a most functional purpose of reinforcement.  There are a number of cannon made and used in the mid 20th century that use it.

[john pike]

'Tis my understanding that muzzle swell was an early form of psychological warfare, used to make the opposing forces believe a gun was larger than it really was.  It became traditional and only disappeared in the final designs of muzzleloading artillery when conservation of materials became important during wartime.  Even the M1857 Napoleon had a muzzle swell.  The Confederate equivalent did not to save material.

I would like to see a credible reference that mentions the purpose of the swell being psychological warfare.  It may indeed have had that effect, if one could even see it at the thousand or so yards away.

But the primary use of the swell is reinforcement.  There are numerous references to the swell (and other enlargements) as reinforcements; as well as the fact that the swell is one of two methods of reinforcing the muzzle (which is one of the weaker areas in the barrel).  The other method is to rebate the muzzle, giving more metal out front to reinforce it.

For example, current US artillery pieces are limited to 4,000 rounds at max charge.  It is common practice (each round is logged and the max-charge equivalent # of rounds is calculated) to check the muzzle for cracks as the 4,000 round mark is approached.  I've talked to several artillery men that have found cracks that showed up within the last 10 or so rounds before the 4,000 mark.

Further, the swell has not disappeared entirely, as it has a most functional purpose of reinforcement.  There are a number of cannon made and used in the mid 20th century that use it.

Heres where i read the sentance.
about 8 paragraphs down
refrence section here,

http://www.hms.org.uk/nelsonsnavycarronade.htm

johnp

[Cat Whisperer]

I remember reading that sentance about the noise - when I posted the reference in the references Sticky.  

I know of no basis for the statement.  The carronade has the unusual muzzle - smaller in outside diameter at the muzzle; and the shorter the barrel the more the muzzle blast.  I am not saying he's wrong, just that this is the ONLY place I've heard reference to the effect.

[GGaskill]

I would like to see a credible reference that mentions the purpose of the swell being psychological warfare. It may indeed have had that effect, if one could even see it at the thousand or so yards away.
 
I read it somewhere; perhaps South Bend Replicas catalog, although I can't find my copy right now to verify that.  I'll try to find the source document.   Plus I think it refers to the earliest guns.  The muzzle swell continually decreased as cannon makers experience increased, with the most modern cannon of the Civil War era (the Ordnance rifle and the Rodman coastal guns) having no muzzle swell.
 
But you have to remember that combat in the days of the muzzleloading cannon occurred at very short ranges until the arrival of the rifled musket (1820 or so) and the bayonet charge was still a mainstay of infantry tactics (especially the British) even in WW I.  So the attacking infantry would have plenty of time to dwell on their opponent's artillery.
 
Although I am not really a student of modern artillery, what I have seen seems to have muzzle brakes so the muzzle may be enlarged to allow threading for the brakes.

[Cat Whisperer]

Ahhh perspective.  When the judge asked the fellow who had been robbed at gun-point if the pistol was a large-caliber handgun the man replied, "From MY view it was a mighty big bore!"

[A.Roads]

Hi all, a newbie here.
It is possible that the reference is to the swell within the muzzle. ie "distinctive swell in the muzzle".

Carronades used on ships, having a short barrel, were found to be detrimental to rigging via the closeness of the muzzle blast etc & so the first few inches of the bore was enlarged which allowed the muzzle flash to be more forward & less sideways which helped greatly apparently.  Whether or not this was louder who knows.  Adrian.

[Squire Robin]

they often had a distincive swell in the muzzle that made them louder.

Howard Blackmore does refer to a "recessed muzzle" on a carronade in his wonderful index on the Tower of London Armouries collection "1 ORDNANCE", but he says it is for "ease of loading".

The two Carron guns I am fixing up don't have it, so maybe it was reserved for the larger, more awkward bores???

Whether it made them louder I wouldn't know.

best regards

Squire Robin

[Cat Whisperer]

Hi all, a newbie here.
It is possible that the reference is to the swell within the muzzle. ie "distinctive swell in the muzzle".

Carronades used on ships, having a short barrel, were found to be detrimental to rigging via the closeness of the muzzle blast etc & so the first few inches of the bore was enlarged which allowed the muzzle flash to be more forward & less sideways which helped greatly apparently.  Whether or not this was louder who knows.  Adrian.

If the first few inches of the inside of the muzzle was made bigger, there is a difference in how it matches the transfer of sound energy to the surrounding air.  It is much like the acoustical coupling from a driver through an exponential horn.

One can observe it with the SMLE jungle carbine flash hider - acts like a megaphone.

Knowing now the characteristic of the muzzle, I stand (sit) corrected.

Thanks for brining this to our attention - and -

WELCOME to the board!

[john pike]

Hi all, a newbie here.
It is possible that the reference is to the swell within the muzzle. ie "distinctive swell in the muzzle".

Carronades used on ships, having a short barrel, were found to be detrimental to rigging via the closeness of the muzzle blast etc & so the first few inches of the bore was enlarged which allowed the muzzle flash to be more forward & less sideways which helped greatly apparently.  Whether or not this was louder who knows.  Adrian.

If the first few inches of the inside of the muzzle was made bigger, there is a difference in how it matches the transfer of sound energy to the surrounding air.  It is much like the acoustical coupling from a driver through an exponential horn.


so is this saying that if you bored out the first 1/2 inch of a cannon muzzle
it would make it louder??

just curious
johnp

One can observe it with the SMLE jungle carbine flash hider - acts like a megaphone.

Knowing now the characteristic of the muzzle, I stand (sit) corrected.

Thanks for brining this to our attention - and -

WELCOME to the board!

[Cat Whisperer]

There is but one way to find out.  Comparative side-by-side tests.

It may be that the remarks were in comparison between the Carronade and another type or maybe not.  If they were comparing two Carronades (one of one barrel inside diameter and the other with the last several inches enlarged) then there is potential of it working in other applications.

What I know from experience - there is a TREMENDOUS difference in quality and amplitude of sound from a 6" speaker by itself compared to attaching an exponential horn (which flared out to a larger diameter).  That matched the output impedance of the driver (a 6" speaker) and the air - each different frequency being matched to the impedance of the air at a different diameter.

Drawing a parallel to the muzzle - the bore is at a smaller diameter and grows to a larger diameter in several inches.  This, to me, would be consistent to my experience with the speaker.  Also it is consistent with my experience with the SMLE Jungle carbine's flash hider (megaphone).

To bridge the gap between theory and practice one needs to verify the theory by building either two identical cannons/mortars with differing muzzles or one cannon/mortar with an adapter ring to change the geometry of the muzzle.  AND measure (using a dB meter) the difference.  I would also make a measurement (spectrum analysis) of the frequencies present and the amplitudes of each.

[Mark 42]

But... if the swell is only to the outside diameter, not to the bore diameter (like an old blunderbus), it shouldn't affect the sound much if at all.

If the bore had a bell shape at the exit, that should act like a megaphone to some extent.

[Cat Whisperer]

But... if the swell is only to the outside diameter, not to the bore diameter (like an old blunderbus), it shouldn't affect the sound much if at all.

If the bore had a bell shape at the exit, that should act like a megaphone to some extent.

That's prety much my theory.  Although some of the blunderbusses flaired out with a thin walled tubing.