A burst 300 pounder

[Evil Dog]

Today has been pretty boring at work so have spent a lot of time rather aimlessly (no pun intended) surfing civil war artillery.  Ran across an image of a 300 pounder Parrot that had burst towards the muzzle.  This happened at Morris Island, South Carolina.



Can you imagine the muzzle end blowing off of a cannon with a 10" bore?   That tube alone weighed around 26,900 pounds and fired a 300 pound projectile !!!  That's the front sight mounted atop the right side trunnion.  Also, I don't see any bands or capsquares over the trunnion... perhaps the weight of that barrel made them unnecessary?

[Terry C.]

From what I've read, muzzle damage like this is usually an indicator of a premature shell explosion.

So the muzzle didn't just fracture and get blown forward, it was most likely shattered and the pieces sent at high velocity in all directions.

Scary!

[Artilleryman]

If I remember correctly, they chipped the muzzle back even and continued firing until it failed again.  How would you like working on that crew?  I think I would be on the other side of the traverse each time it fired.

[RocklockI]

check out the sawed off lumber even with the fracture . No trunion caps needed .

[seacoastartillery]

     The following information came from Artillery and Ammunition of the Civil War by Warren Ripley and The Big Guns – Civil War Siege, Seacoast and Naval Artillery by Olmstead, Stark and Tucker.  These two books are absolutely the best reference works ever written on the subject of big Civil War Cannon and essential for our business and we carry them everywhere.  They have logged about 80,000 miles with us as we have searched the United States for cannon since 2002.

     Only three 10” Parrott Rifles saw service in the war, all on Morris Island in the “Parallels” south of Confederate Battery Wagner by 1,900 yards and south east of Fort Sumter by 4,290 yards.  Fortunately for us the one in the photo was extensively documented by General Quincy Gilmore’s artillerymen.  He also ordered a drawing of the muzzle face of this piece made as it was the very first of this largest size Parrott used during the war.  It was cast at West Point Foundry in 1863 and marked as  No. 1.   It weighed 27,030 pounds and was inspected by Alfred Mordecai, the younger.  The only gun in Battery Strong, it pounded Fort Sumter unmercifully, and, despite the problem with a defective shell burst at the 27th round, it performed well for 371 more rounds after having the jagged muzzle chipped back beyond the fracture. 

     This gun used it’s gain twist rifling, ( zero twist at breech to one turn in 30 feet at the muzzle) to good advantage in reducing the strain of the 250 pound projectiles on the tube during acceleration to approx 1,100 fps.  Those big shells were propelled by 25 lb. charges.  Elevations of 13 degrees to 13 degrees 30 minutes were used to loft those shells the two and a half miles to Fort Sumter’s south east salient which, over time, was pared almost to the water’s edge.

      The Federal Army’s Commander and Chief Engineer on Morris Island, SC was General Quincy Gilmore who was intensely interested in large artillery and wrote quite a bit about this particular 10” Parrott Rifle.   “No one”, Gilmore said, “could witness it’s performance during the bombardment of Sumter and notice the terrible crushing effect on the masonry of that place, the ease with which it was worked, and it’s remarkable accuracy at a distance of over two miles and a half, without being filled with admiration and wonder”.  I read an account in print a long time ago, source unknown, about a CSA Artillery Officer stationed at Fort Sumter during the Federal siege who would run to the point of attack by this 10” rifle and listen to the whirring and grinding of these huge shells as they continued to rotate after striking the curtain wall of the fort.  He would then estimate their distance from his side of the wall based upon the loudness of this grinding sound as they lost RPM.  He would make decisions on when to evacuate that particular casemate or remove ready powder supplies and fill the casemate with rubble and dirt based on these observations.  We believe that most of the fusing for these large shells was of the paper type as maximum penetration was desired before detonation.  Blind shells could have been used as well for maximum penetration and deep masonry fracture.  Percussion fuses were not always trusted to allow the shell to penetrate to it's deepest extent.
   
     Of 42 cast, 13 survive today. 

Regards,  Tracy and Mike

[Terry C.]

"despite the problem with a defective shell burst at the 27th round, it performed well for 371 more rounds after having the jagged muzzle chipped back beyond the fracture."

371 rounds after the muzzle was blown off? Brave souls indeed!

[Double D]

I wonder if the gain twist had anything to do with the fracture.  Tremendous forces had to come to play with a shell that big.

[Terry C.]

It was a defective shell. Not going to make much difference what rifling method is used when the projectile goes boom in the muzzle.

If anything, the fact that the damaged barrel survived so many subsequent firings is a testament to the effectiveness of the gain twist in reducing stress.

[Victor3]

I wonder if the gain twist had anything to do with the fracture.  Tremendous forces had to come to play with a shell that big.

 Me too.

 Starting out at the breech with the rifling engraved on the shell at a slow (or no) helix, then requiring a change to a faster helix along down the bore amounts to "cold forging" the engraving to a different angle as it's moving. I imagine this would put a lot of stress on the barrel, considering that the helix change happened over a very short period of time.

[Double D]

Thats what I was thinking also.  Could the rifling have broken loose, could stress cracking occured. Combine this with a bad shell design and the whole problem is exacerbated.  Seems to me that have read  that these  kind of problem was common in the Parrot.

[seacoastartillery]

   Let's see, not being a politically correct kind of guy, and at the risk of getting even MORE Coal in my stocking on Christmas morning, this time from a learned machinist in L.A. and a Moderator Emeritus in Cut Bank, MT, I should approach this rebuttal with just the facts, delivered respectfully.  So, first take a look at the width of the rifling in the photo below taken in the northeast on our last research trip.  Since the bore diameter of the 10" Parrott is 10.00 inches, the circumference of the bore is 31.1416 inches.  Their are 15 equal width grooves .100" deep and 15 equal width lands.  All 30 of these features are equal width so:  31.1416" / 30 = 1.0472" WIDE   Do you fellows really believe that a flimsy piece of brass barely attached to the base of these larges shells, designed to be engraved by the rifling, could really cause the failure of rifling lands OVER a full inch wide and ONLY 1/10th that high?  To call that size rifling land substantial is like calling the Rock of Gibralter substantial.  It's obvious.  Come on guys, isn't all that cast iron going to cut that flimsy little brass sabot band like a bow-saw through a stick of butter?

     Working at the Naval Gun Factory for years before WWII, Ray E Rayle learned a multitude of important facts about cannon and the most effective tubes and why they are that way. Materials, length, rifling forms, throat inserts, etc. In his excellent book, Random Shots, he writes, "Use of gain twist rifling in a high rate of fire, larger gun, was found to give a longer life barrel life than uniform twist rifling  where thin walled shells demanded unusually high twists."

     Also, just yesterday I was re-reading Gen. Gilmore's report of Parrott tube failures during the Seige of Fort Wagner on Morris Island, SC.  Paraphrasing a portion of that report, we learn this:  "Of the more than 50 burst tubes, almost all failed immediately in front of the reinforcing band to the rear of the trunnions".   No, I think the secret to the failures of these hard-worked 30, 100, 200 and 300 pdr. Parrott lies in the fragile nature of the shells fired by them. After all, this is the area where the rifling is straight ahead with almost no twist at all.  Certainly the lands would not be twisted off in this area, even in the unlikely event that they might be at all? The most probable cause of all these blown-up Parrott Rifles came out in our conversation with the Paulson brothers in December of 2006 at their artillery shop office in Clear Lake, Wisconsin.
     As Mike rolled an original 100 pdr. Parrott bolt around on the floor, they explained why they believed that failure of the shell castings were a far more likely cause of tube failures during the war than any other cause.  We got lessons in casting technology, wall thicknesses, shock of firing, shape of fragments, and probable jamming of fragments causing an immovable obstruction or blockage at the time of peak pressure.  That's why so many failed in the area of MAXIMUM SHOCK to the shell.  We learned a lot more than that during our visit, but the discussion about Parrott tube failures is presented accurately here.  The blown-up tube in Evil Dog's historical photo is an anomaly and probably indicates catastrophic fuse failure.

     Besides, can all these firearms types, companies and individuals be wrong?

                Colt cap and ball revolvers
                German, WWII high velocity anti-tank guns
                Harry Pope
                Burnside Carbines
                S&W .460
                Kreiger Barrels
                Bartlein Barrels
                Rock Creek Barrels

Regards,

Tracy and Mike


Robust 10" Parrott rifling.  Look at that rifling; it's about as solid as it gets.

[Double D]

Six months ago I would not have consider the possiblility of a projectile stripping rifling or transmitting shock while passing down a barrel.

I have known for years that the surface of steel can be burnished and surface hardened from the repeated pressure and friction of a brass rod.  I also know and have experienced the surface hardening of chamber particularly in magnum or high intensity calibers. This is apparently from repeated firing and slamming of the brass case into chamber walls.  I have experienced this when setting barrels back to clean up old chambers and throat erosion particularly in the .22/250 and the 7 MM REM Mag.  The reamers just seem to skate across the surface of the old chamber until the old chamber has its surface roughed up. Now I don't believe this a dangerous condition, in fact it's probably a benefit. I have never notice in the bore.  I think the reason for this is by time the reamer gets to the bore its cutting the micro thin side of the hardened metal and not the flat surface.

I also don't think this surface hardening would be cause for barrel failure in a Parrot or a .22-250. 

Several months ago I had a chance to talk with an engineer involved in the development of depleted uranium rounds in the Abram tank. I said I need some of that DU for some long range bullet for my Martini's.  He got a good laugh and no you don't.  After the first round there would be no rifling left in your barrel.  He explained that DU has such a large mass that when fired in a rifled barrel the rifling was not strong enough to overcome the inertia of the projectile and was stripped out of the barrel.  He said when the tried a 5.56 DU round part of the rifling was found sticking out of the barrel and the rest laying on the ground. The rifling was strip full length.  I believe Kreiger Barrels has reported this also.

Thinking of the burnish/surface hardening effect of soft metal on hard metal and the need for the metal in a rifled barrel to be strong enough to resist and overcome the inertia of the projectile, the next logical question in reviewing the Parrot failure is: "I wonder, could it have been...?  Seems even more reasonable as if I remember right, the Parrot failures were metallurgical. 

The whole theory my have nothing to do with fault, but is food for thought. Nothing else.

[GGaskill]

He said when the tried a 5.56 DU round part of the rifling was found sticking out of the barrel and the rest laying on the ground.

That is very interesting.  One thing most people don't know about uranium is that it is very hard in addition to its great density.  I wonder if the DU bullets were bore size; if so, I can easily see how the rifling could be pushed out the end of the barrel.  With hard bullets, one needs a compliant jacket material. 

Consider standard hardened steel AP bullets; they have a copper jacket so the steel doesn't bear directly on the rifling.  A DU bullet would need to be a bore rider and have a teflon coating or be a core in a copper jacket to successfully negotiate a rifled bore without destroying the rifling. 

The angular momentum (AM) of small lead bullets is typically less than 5 lb-ft so the denser DU bullet at the same RPM would have only about 20% more AM.  And since its greater density would require a slower twist for stabilization, the AM would likely go down to the lower figure since the RPM would be less.

[Terry C.]

5.56 DU round? This had to be someones workshop project.

AFAIK the smallest caliber that currently uses a DU penetrator is the 20mm round for the Phalanx CIWS. The penetrator core is smaller than the bore diameter and never comes into contact with the rifling.

A 5.56 diameter DU bullet in an AR would be a rifling remover.

[Double D]

There are smaller DU rounds than 20 mm.  He displays a 50 cal but says there are smaller calibers for special applications. Only the 30mm GAU doesn't use a discarding sabot.  The sabot of course is to protect the barrel while imparting spin to the projectile. 

I didn't mean to drift this to discussion to DU.  I simply wanted explore the idea that gain twist and poor metallurgy might have had something to do with Parrot failures. 

[Terry C.]

There are smaller DU rounds than 20 mm.  He displays a 50 cal but says there are smaller calibers for special applications.

Must be a need to know thang.

And I don't need to know.


And you're right, this has gotten way off-topic.


Now if you'll excuse me, there's a strange looking black helicopter circling overhead...

[Victor3]

   Do you fellows really believe that a flimsy piece of brass barely attached to the base of these larges shells, designed to be engraved by the rifling, could really cause the failure of rifling lands OVER a full inch wide and ONLY 1/10th that high?  To call that size rifling land substantial is like calling the Rock of Gibralter substantial.  It's obvious.  Come on guys, isn't all that cast iron going to cut that flimsy little brass sabot band like a bow-saw through a stick of butter?

 Well yeah, but ya see, I....Ummmm....

 No, I guess not.

 I didn't take that into account. I was thinking the projectile had more of itself engraved into the rifling.

 You guys are still leaving out a lot of info about how it could have happened though.

 I hear tell that the CSA had this secret big magnifying glass that they would use to focus sunlight on the barrel of Union cannons, causing the........

[seacoastartillery]

     Victor3,   I was thinking about what you wrote in your last post: 

I hear tell that the CSA had this secret big magnifying glass that they would use to focus sunlight on the barrel of Union cannons, causing the........

     As I thought about that, I began to remember a few things about the Union "Death Ray" that was actually used during that siege of Confederate Battery Wagner on Morris Island, SC.  No, it wasn't really a "Death Ray", but for those days it was a pretty spectacular defensive weapon as used during the siege.  Gilmore had two very large Calcium Lights set up at about 750 to 800 yards from the Confederate fort to illuminate it entirely every night and blind the Confederate sharpshooters who constantly harassed his sappers as they dug their trenches closer and closer to that large sand fort.  Gilmore had 40 or 50 people engaged in producing the hydrogen and oxygen gases required to burn within the limestone cylinder to create the intense light which was then directed to the forts ramparts by large parabolic reflectors.  Stage hands set up calcium lights or "Lime-Lights" up until the 1920s to showcase the stars of those days.  It was a long-lived  invention used for 70 plus years.

     During the last 12 hours of the siege, Gilmore ordered a land and naval bombardment of the place and at night a Federal flag flapped in a light breeze at the head of the sap only 50 feet from Wagner's ditch.  The sappers had placed it there upon request of the Navy which could not tell exactly where the Fort Wagner mound ended and the Federal occupied sand dunes started.  At night the Navy moved in pretty close to give the fort a full measure of accurate fire.  Mostly the gunners aimed low so as not to over-shoot the fort.  One of the 11" or 15" naval rounds richocheted off the ocean and propelled a mullet into the fort!  Confederate troops evacuated the fort under this terrific bombardment just six hours before a Federal infantry attack was to begin. 

Regards,

Tracy and Mike

[JeffG]

I wonder if the gain twist had anything to do with the fracture.

I have a book for you to read...."A Quest for Glory"  Robert J Schneller. Although it is a biography of Admiral John Dahlgren, it goes into detail what gun founders, and arterialists were going through during this period, in regards to casting quality.

Dahlgren was of the opinion that cannon should be cast oversize, and turned to size to maintain cast metal integrity.  Many of his contemporaries, including Parrot, did not adhere to this concept.

I think that the lack of trunion caps and sawn through lumber, suggest that the photo was taken after it had been captured, and put out of commision so the (advancing)troops could move on without the fear of the gun being used again.