Author Topic: "What Happened to Your Weapon, Marine?" "It Blew Up, Gunny" (Read 992 times)

seacoastartillery · « **on:** August 14, 2008, 03:31:12 PM »

An old friend of ours, a U.S. Marine, stopped by today to get the 50 cent cannon factory tour. He brought along a real treasure from our gunsmithing school days together, 30 years ago. He had us clean up the exterior of a free bronze casting he received from his cousin, a foundry school student. We all agreed it was to be a wall hanger because of EXTENSIVE POROSITY in the bronze. Like a lot of people, he wanted to fire it at least once before plugging the vent and retiring it. We all decided to do this under CONTROLLED, TEST PIT conditions for safety. One .730" Dia. lead ball and an appropriate powder charge were used.

If you buy or are given a free cannon which exhibits porosity, be WARNED; don't fire it with blanks or ball loads as it could easily end up like this one. Porous castings of any metal are WEAK and DANGEROUS!! The proof is in the pics below.

FYI,

Mike and Tracy

A side view showing the amount of damage done by a single shot.

Porosity was extensive, even the cascabel had a bunch.

Porosity in the chase and also in the trunnion material.

The bulge on the right side opposite the "flap" of bronze is more proof of this tube's weakness.

More porosity evident on the muzzle and the 3/4 inch bore.

EL Caz 66 · « **Reply #1 on:** August 14, 2008, 04:15:22 PM »

Oh Boy!!

Thanks for the Warning... Yikes...

cannonmn · « **Reply #2 on:** August 14, 2008, 05:22:32 PM »

Thanks for the nice pix. I think different people will interpret this in various ways. I think it is somewhat remarkable that the displaced piece

1. Remained attached
2. Was in fact only one piece

Blown replica and original guns I've seen often had many ejected pieces. If the metal was as bad as suggested, I'm really surprised it remained attached, which speaks well of the metal.

The photos really make me wonder exactly what weight powder charge was used, what kind of powder, whether ball was patched or wad was used on top.

??

It just doen't make sense to me that even in a gun with visible porosity, such destruction could occur with a normally-safe load. I've fired original guns that had lots of visible porosity at the breech, and fired them many times with significant charges and full-weight shot, and had no problem, but maybe I was just lucky.

cannonmn · « **Reply #3 on:** August 14, 2008, 05:25:35 PM »

...and if I make this one more post, it puts me over 700!

Double D · « **Reply #4 on:** August 14, 2008, 05:27:04 PM »

Marine + Brasso = Bronze imbrittlement

seacoastartillery · « **Reply #5 on:** August 14, 2008, 06:37:39 PM »

Douglas, We are pretty sure he polished this piece a bit AFTER we tested it in the pit behind the 5 Ft. diameter Cottonwood, not before, but we worry about those bronze signal guns near the main flag pole on those Army posts I was assigned to.

Cannonmn, 100 grs. of Goex Fg BP is NOT excessive for a 75 Cal., six pound cannon. No patch or wad was used. The ball was a rattle fit in the bore. For everyday firing of a well cast bronze gun in our experiece, 60 or 70 grs. is a better target load for a six pound cannon of this bore size. With a breech wall thickness of 1.0", a solid, bronze gun of this size should stand a proof of 200 grains of BP easily. I don't know how to explain the porosity present in this casting other than to say, with no exaggeration, that, when we drilled the bore, the surface inside was about 50% air and 50% bronze. Now is it clear how compromised this gun's metal was??

The outer metal was much better than that in the gun's interior. We think that this fact could contribute to the hinge-flap effect of the single, blown piece.

EL Cazador 66, You are certainly welcome and thanks for that recent post of those ancient artillery pieces that Dom made for you. He certainly does a might fine job! We love his cannons.

Mike and Tracy

GGaskill · « **Reply #6 on:** August 14, 2008, 07:09:05 PM »

Assuming the barrel was sand cast horizontally and with the top up, it is not beyond possibility that the porosity simply floated to the top of the mould cavity leaving it ready to fail. Shooting cannon were normally cast vertically with the breech down with a large deadhead/shrink feeder above the muzzle so that shrinkage porosity would occur in the cutoff/noncritical parts of the barrel.

It's too bad that these casters of non-shooting pieces bore more than an inch or so of the bore. It makes the owners want to shoot them since drilling a vent is so easy. That barrel would have made a nice desk top piece intact.

KABAR2 · « **Reply #7 on:** August 15, 2008, 02:01:59 AM »

It would be good to know what type of bronze was used, or was this actually brass?

EL Caz 66 · « **Reply #8 on:** August 15, 2008, 02:25:11 AM »

I would say when in doubt, have seamless sleeve pressed into your brass or bronze barrel. I had this done by Dom Carpenter on this little cannon and so far all is well.

Click on the link

http://www.youtube.com/watch?v=KbbNt5RPzbY

Victor3 · « **Reply #9 on:** August 15, 2008, 03:13:47 AM »

As my Dad used to say every time we passed a wrecked car on the highway...

"A little rubbing compound should take that right out."

I used to machine thousands of tombasil (silicon brass) castings. Every once in a while we would come across one that we called a 'sponge' due to very high porosity. We could sometimes feel the lighter weight of these before machining and toss them into the scrap bin before wasting time on them.

My most vivid memory of these castings is when I hit a 1/4" ball-bearing cast into one while facing it with an 8" shell mill...

Mike Britton · « **Reply #10 on:** August 15, 2008, 03:35:59 AM »

You guys seem to know about brass breeches for muzzle loaders. Many years ago, I picked up a .58 cal. carbine that is a clone of the "Texas Mowery" rifles of days passed. This rifle, unfired, is a cool little, short,22", marked only .58 cal, and with, I assume the serial number of 330. It has a state of Texas seal inletted into the butt. No other marks exist.
Now that I've put you to sleep, the guy I got it from sold it to me for $50 only if I promised to never fire it because the breech plug is brass.
The whole "action" is brass. I've shot many Italian copies of Colts that had brass actions, and yes they will stretch if pressured too much, but I've never seen one let go yet.
Would you guys consider shooting this rifle? what kind of load would I start with? My .58 cut down Zouave is happiest with a Minnie over about 90 grs. I know the clone will give up with that kind of load, but there should be some kind of load that this little rifle can live with. Thanks, Mike

cannonmn · « **Reply #11 on:** August 15, 2008, 04:56:25 AM »

The construction of your carbine introduces a new problem that really hasn't been discussed here, that of electrolytic corrosion. Powder residue and mosture will get in between the brass plug and the steel barrel, if it hasn't already, and will eat up the threads, eventually making the plug want to become a heavy projectile headed for your shootin' eye.

Also the brass threads have nowhere the strength that steel threaded plug would have.

That's way too many unknowns, or "failure factors" for me to risk my life with. I've had some friends seriously injured and two of them killed outright while shooting antique rifles that failed and put pieces of the action into their brains, so I'm a little cautious I guess.

I say hand it on the wall and admire it, then go out and get a carbine with steel-on-steel construction.

Mike Britton · « **Reply #12 on:** August 15, 2008, 08:21:38 AM »

That's what I needed to hear from someone more familiar with front loaders than I am.
I have other stuffers, my favorite being a clone Zouave cut down to carbine length, and an absolute ball to shoot.
My son named him "Lenard", and I wouldn't hesitate to take him on a hunt anytime.
.58 cal and 85-90 gr. of powder! yessir!
The brass rifle can hang on the wall for another 20 years. How do I disable it so some idiot won't try to load it? Can I fill the nipple hole full of epoxy and then screw the nipple back in?

Tropico · « **Reply #13 on:** August 15, 2008, 08:56:20 AM »

Rant ., I dont mean to offend ., but this stuff is an overkill issue thatsunsupported by actual facts and needs cleared up.

Amazing

I been shooting a Brass barreled David Pedrosoli Queen Anne ( a huge name in gun manufactor - theyve built more than anyone on this board) as well as A bronze Blunderbuss for years and it was done so in history for years ., perhaps someone here can show us some evidence of Pedrosoli gun failures? After all they are approved to be sold for the purpose of shooting in this country. Can we have the names of these destroyed friends? I 've been in the re-enactment for years and I dont know any. This is getting more interesting by the minute. Seacoasts friends cannon was a blem ., "Porous" it wasnt the fact it was yellow metal. If thats the case all Bronze guns should be destroyed NOT saved. I will keep shooting my bronze swivel while you fight rust. And by the was my brass cannon 1"bore Brooks isnta problem either. It has a 1"wall same as the one above. Also my first Swivel was a cast ., we fire 1"Dumb-Dumbs all the time with it. Santa Dave and Jeeper1 werent killed during these events.
Rant over

Heres a couple of my "ünsafe"guns that i fire all the time.

Rickk · « **Reply #14 on:** August 15, 2008, 09:45:14 AM »

brass 12 gauge flintlock bluderbuss... lotsa fun

cannonmn · « **Reply #15 on:** August 15, 2008, 01:14:15 PM »

Quote

Can we have the names of these destroyed friends?

Friends killed by rifles that failed included Glenn deRuiter and Scott Johnston.

dan610324 · « **Reply #16 on:** August 15, 2008, 01:37:18 PM »

this is an extremely good sample to show people what can happened when shooting pieces that wasn't made to shoot .
thank you very much guys that you posted this pictures . I will save them to show others what can happened .

there is an old Swedish proof testing rule from approximately 1680 - 1700

first shot , half powderload and one cast iron ball
second shot , full powder load and one ball
third shot , double powder load and one ball
fourth shot , full powder load and 2 balls
fifth and sixth shot , full powder load and one ball in both shots .

after that testing they was safe to use with full service loads by the army rules 300 years ago .
that testing should be done by the foundry with one high military officer there when the tests was done .

I believe this are the minimum rules to follow today also for cast barrels .
if you ain't an professional foundry with extreme high tech equipment you can never be sure what result you got ,
from one casting to another .

this pictures show that bronze is an very good cannon material , but I'm still a little confused .
it ain't normal that an bronze barell open up that much, could be because of extremely bad casting .
usually bronze barells just open up an crack along the barell .

hi john , the replica and originals you talking about are they cast iron or bronze ??
I know cast iron often or maybe always spreading scrap metal pieces all around when they explode , but I never seen that happened with an bronze cannon if they are loaded with blackpowder . if you got any photos it would be very interesting to see them .
I'm looking for as much info as possible on cannon accidents , its very good to have when teaching people some basic knowledge about cannon shooting . AND WHAT CAN HAPPENED IF YOU DONT DO IT IN AN SAFE WAY .

Don Krag · « **Reply #17 on:** August 15, 2008, 02:02:45 PM »

Dang! A 100g Fg charge did that! Yikes! Dynamic pressure is an interesting beast. Any video? I have an old radiation shield made from 3/4" lexan that I use inbetween my camera and "experimental set-ups" in case of catestophic failures.

You could always melt it down and make a lot of buttons now.

dan610324 · « **Reply #18 on:** August 15, 2008, 02:14:43 PM »

DONT MELT IT

if the owner don't want it I can buy it to use as an frightening sample

seacoastartillery · « **Reply #19 on:** August 15, 2008, 03:34:14 PM »

Well cast bronze guns are just fine; we would not hesitate to use them within normal safe practice limits of charge and correct weight of ball.

One LAST time: Bronze IS NOT the problem, the CONDITION of the Bronze Casting WAS THE PROBLEM. It was fatally flawed in that it was EXTREMELY POROUS which means it had a lot of air where the bronze should have been. Mike and I let the owner know what could happen; he insisted on testing it one time only. All of us tested it SAFELY!!! Nobody was hurt. Period. Sorry, no movies; this was thirty years ago.

FYI

Mike and Tracy