Kaboom - cira 1961 or so

[GGaskill]

A vent that large would have significantly weakened that area and led to stress concentrations at its edges.

Plus, what about the newspapers?  Were they just pushed in or pounded as we have seen some if the ignorant showing us on youtube?

[Cat Whisperer]

DD - I can't agree.  The corrosion (blackening) would have been even, had it all occured at once.  I've seen the cracking in many other places (bolts holding hydraulics together) that indicate over time several stages of cracking.

[Cat Whisperer]

A vent that large would have significantly weakened that area and led to stress concentrations at its edges.

Plus, what about the newspapers?  Were they just pushed in or pounded as we have seen some if the ignorant showing us on youtube?

Not pounded in.  How much?   ??  Too far back.

[Double D]

DD - I can't agree.  The corrosion (blackening) would have been even, had it all occured at once.  I've seen the cracking in many other places (bolts holding hydraulics together) that indicate over time several stages of cracking.

You have the advantage, you have the materiel to physically examine....I know a characteristic of all guns that  have seen that failed was sooting.

[Cat Whisperer]

Yup.  Home court advantage.

I don't disagree with sooting.  This is a deep blackening.

[KABAR2]

Was this with a dry or wet wad over the powder? Wet wads tend to increase pressure.....
that combined with blasting powder would probably be enough to cause catastrophic failure.....

[Cat Whisperer]

Was this with a dry or wet wad over the powder? Wet wads tend to increase pressure.....
that combined with blasting powder would probably be enough to cause catastrophic failure.....

Agree.  That's one of the techniques (mud) they (artillery OCS) taught us to use to destroy a cannon if it had to be abandoned.

[dominick]

I don't think it matters how little wadding was used if all that darkening is from previously fractured metal.  All it needs to is begin to fail at one weak spot, the vent and possibly that dark spot near the vent, and it will peel open. 

[KABAR2]

I don't think it matters how little wadding was used if all that darkening is from previously fractured metal.  All it needs to is begin to fail at one weak spot, the vent and possibly that dark spot near the vent, and it will peel open.  

So previous firings with powder designed for mining and fracturing rock began & continued the process of fracturing
the the metal until catastrophic failure occurred.

[Double D]

I don't think it matters how little wadding was used if all that darkening is from previously fractured metal.  All it needs to is begin to fail at one weak spot, the vent and possibly that dark spot near the vent, and it will peel open.  

So previous firings with powder designed for mining and fracturing rock began & continued the process of fracturing
the the metal until catastrophic failure occurred.

Tim mentioned sodium nitrate...Could this fall into the same category as some warn about the black powder substitutes such as Pyrodex and a Triple 7. The residue from firing of substitutes  attacks the zinc in the cartridge alloy weakening to failure.  Here is an example.

.577/450 brass from  Kynoch at  $5 a case.  Never fired with anything but Triple 7.  Brass was cleaned and stored for two years while I was in ZA.



Pyrodex also has a history of doing this.

[Cat Whisperer]

Important to note here is the lack of good info on the usage prior to about 5 years before the event.  But in that time it was shot perhaps 10 times a year (around the 4th).

Are not some of the FA (vs FG) powders of a different base than potasium nitrate?

[GGaskill]

Ammonia in the firing residues will cause brass to accelerate its cracking.  One of the reasons why brass fired with non-smokeless propellants should be soaked in water as soon as possible after firing, especially those expensive cases like .577/.450 or .45-120.

Probably copper alloy barrels would benefit from rapid and repeated cleaning.

[Double D]

FBB blasting powders are Sodium  Nitrate based.  I am wondering if the residue of firing sodium nitrate in a copper alloy tube might have similair corrosive effects that occurs from the residue of  powders with postassium perchlorate.

[GGaskill]

Ammonia is NH₃ or NH₄OH if dissolved in water.  It is a combustion product of all nitrate based propellants to some degree.  So it will be present and available to react with copper alloys whether cartridge cases or cannon tubes.  

It accelerates stress corrosion cracking; it is demonstrated dramatically when a bore has been cleaned with ammonia to purge it of copper fouling and the ammonia is not removed before firing.  The brass case neck will frequently crack within a minute of firing because it has had stress added by expansion from firing and an excess of ammonia is present that adds corrosion to the stress.  

So one should expect this kind of problem in a copper based barrel unless it is cleaned soon after firing.  And another later cleaning wouldn't hurt.  The use of the sponge after each shot was a major part of dealing with this problem in bronze artillery and skipping the sponging step had to accelerate stress corrosion cracking in bronze barrels.

[Cat Whisperer]

1018 is sounding better and better!   

[RocklockI]

I think Doug was on to something right off . Because of the nearly complete lack of tearing it is just sheared off , it looks like a very high pressure fragment .

Maybe it fractured and cracked along the way ....finally it let go with far less resistance on that shot .

Very odd in any case .

[Cat Whisperer]

I'll do a closeup.  LOTS of tearing.  Also, LOTS of pressure.

[Cat Whisperer]

Hand held (Might be some movement).
First is flash, others sunlit.

I see lots of tearing.  I'm impressed with the fiberous look.  I veiw the bright areas as most recent tearing.  Tough to call on color/corrosion of deeper cracks, but some look newer deeper in.

[RocklockI]

Yes Tim that is a good word to use , "fiberous look" . just ripped and pulled apart .

I have a bronze cannon that was blown up by me many years ago it has the same look , but it is also clearly split along it's length and the gun did not break into many parts .

At best yours looks like a massive overload WITH alot of packing .      Yea I know ....duhhh 

Boy did I feel like a fool when I blew my gun up .....

It sure starts alot of conversations though .

Lay it on your coffee table ...people will look at it and say ....... did that cannon blow up ..... ?  "Why yes it did , how nice of you to notice " .

Gary

[Zulu]

Gary,
Post pictures of your blown up gun.  We'd like to see them.
Zulu

[Cat Whisperer]

...

Boy did I feel like ...

Gary

That is SOOOOO much better than NOT feeling anything anymore!   

[dominick]

If you ran a saw thru a piece of casting like that and look at the cross section, I wonder how solid the material would look.   
10X magnification?

[Parrott-Cannon]

Blasting powder because it is made with sodium nitrate has a higher oxzidator content over time could this lead to break down of the bronze? 

[Cat Whisperer]

If you ran a saw thru a piece of casting like that and look at the cross section, I wonder how solid the material would look.   
10X magnification?

I'm sure that there are LOTS of  little cracks - as one can see some of the large ones.

[Cat Whisperer]

Blasting powder because it is made with sodium nitrate has a higher oxzidator content over time could this lead to break down of the bronze? 

It was used on the last shooting session.  I don't recall it being used in years prior but may have been - as I recall the powder came out of a red can in years previous.  But that doesn't answer the issue you raised. 

[Cannoneer]

is it really a bronze barrel ??  or could it be brass ??

Of course it can only be speculation as to what that barrel was actually cast out of, and what percentage of metals were combined to form the alloy. I wonder what a metallurgical testing lab would charge to run an analysis? They might also be able to form an opinion as to the cause for the fibrous/spongy apearance of the fragmented metal.

I've got a few cannons that I know to be brass, along with one that was "described" as being cast bronze, and after reading CW's thread (and viewing the pics) I don't mind saying that I don't feel as comfortable as I once did about firing them.

[Cat Whisperer]

...
I've got a few cannons that I know to be brass, along with one that was "described" as being cast bronze, and after reading CW's thread (and viewing the pics) I don't mind saying that I don't feel as comfortable as I once did about firing them.

I don't enjoy saying, "Good".  That certainly was not my intent on this thread.  But, caution is OK.  Better too much caution than too little.

[GGaskill]

The thing to do would be find a scrap dealer with one of the "ray guns" that analyze metals.  I looked into getting one of these but a rebuild was $18,000 and I couldn't bring myself to buy that expensive a toy.  Maybe when I hit the lottery.

[Cat Whisperer]

The thing to do would be find a scrap dealer with one of the "ray guns" that analyze metals.  I looked into getting one of these but a rebuild was $18,000 and I couldn't bring myself to buy that expensive a toy.

We tested a new one ($30 - 40k) in the plant a few years back.  I checked everything I had any questions about too.

(The device bombards the material with some flavor of radiation and looks at the emissions and gives a printout of ALL the elements present.)

[Double D]

I got it!!!

As we size and fire, size and fire cartridges and after a period of time if we don't anneal the cases they will split...I wonder could this be what happened to this cannon?

I did a paper on this in college.  The paper was to determine if there was anything consistent on how brass work hardened.  I wasn't able to come up with anything predictable but we were able measure the increase in hardness from shot to shot sizing to sizing and the most increase came from shooting.  We were able to reverse the hardeneing by annealing. 

The only other thing I can remember Federal Ammunition  provided all the brass and a large amount of research material. Thank you  Federal.

So I wonder, do we need to anneal our brass guns?