2. The 5"/54 Mk 45, Mod 0 - 2 gun mount has an approximate barrel life of 8,000 rounds. There are two different types of gun tube, the Mk 19, Mod 0 and the Mk 19, Mod 2, the Mod 0 is a two-piece tube with a replaceable barrel liner, and the Mod 2 with a mono-block tube. In the case of the Mod 0, only the liner is scrap.
The 5"/62 Mk 45, Mod 4 gun mount is a mono-block tube and uses a little hotter ammunition and has an approximate tube life of 7,000 rounds.
My source was a retired Bureau Naval Ordnance employee who was assigned to the organization making the current Naval 5 inch guns. He worked Naval cannon his entire career. I was asking him questions during breaks in a rifle match, maybe he got the number wrong, maybe I heard wrong, maybe 700 rounds were the five inch cannon that had to be replaced because they were not maintained (!), or maybe I heard wrong. However, for credibility, what is your source?
You might want to re-check your source. Parrott Rifles, if they did fail, tended to blow out near the muzzle rather than the breech, which made them safer for the crew. And, the cause of these blow-outs was usually a premature explosion of the projectile (an "in-bore" in modern parlance), not ant inherent weakness of the gun. Lastly, if they only lasted 300 rounds, the Union Army at Gettysburg would have had no artillery to deal with Pickett on the third day....
During the siege of Mobil, Farragut lost more men to Parrot gun explosions on his ships, than he lost to Confederate counter-battery fire.
Again, NO.
Union losses in the Battle of Mobile were 151, 94 of those were lost on the Tecumseh. You might be thinking of the USS Juniatd's 100 pounder burst while firing on Fort Fisher (Charleston) that killed five sailors and two officers. In typical sensationalist newspaper fashion, the New York Times reported that "hundreds killed by Parrot guns failure". In this particular incident, the most likely cause was premature explosion of the explosive shell.
By 1865, of the 352 100 pounder Parrot guns delivered to the Navy alone, only 19 burst in service, and none of the 200 pounders had failed. And, many of these firing in excess of 1,500 rounds during the course of the war.
I had some things right. It was the Civil War, it was Parrot guns, and they blew both in the service of the Army and Navy. I was wrong about Farragut, the worst blow ups in the Naval service were at Fort Fisher under Admiral Porter.
Large Parrot rifles had the worst record of any Union cannon for premature bursting of both rifles and projectiles. The statistics you present on the 100 pounder Parrots ignores the other types that were on the battlefield. Surely the reference you used accidentally omitted the other Parrot calibers. Of 100 large caliber Union cannon that cracked or burst in action during the war, 93 were Parrots: three 4.2 inch, sixty 6.4 inch, nineteen 8 inch, and one 10 inch.
Still, of the 100 pounder Parrots, the blow up rate is 6%. Is that acceptable for the modern Army Ordnance Bureau, that of 100 items built, only 6 out of 100 suffer catastrophic failure?
From the
1869 Report of the Congressional Committee on Ordnance
Each system of guns introduced in our service has been subject in proof to tests supposed to demonstrate beyond question its ability to perform the work required of it, but each has failed when submitted the real test of service. In the operations upon Morris island 22 large guns was the greatest number mounted at one time, yet 50 in all burst during the siege, as is shown by the evidence of General Gillmore. In the attack on Fort Fisher all the Parrot guns in the fleet burst, according to the report of Admiral Porter, By the bursting of five of these guns at the first bombardment, 45 persons were killed and wounded, which only 11 were killed or wounded by the projectiles from the enemy’s guns during the attack.
11 Nov 1867 Commodore R.B. Hitchcock:
2. Q. What is the ordinary proof to which smooth bore or rifled guns in the naval service are subjected?:
A. In making a contract or engagement for any special class of guns, they take the first of that class and submit it to what is termed extra-ordinary proof, that is, a thousand rounds of service charge. The others are supposed to be duplicated of that gun. They are submitted to 10 charges of service rounds.
3.Q. You take on gun of a class?
A. Yes. For instance, if you were going to make 9 inch guns you would take the first and submit that to extraordinary proof of 100 rounds.
4.Q. The extreme proof is 1,000 rounds?
A. That is the initiatory proof of a class of guns. These others are supposed to be duplicated, and before reception in the service they are fired 10 rounds.
10.Q. What is considered the measure of the life of a gun in the naval service.
A. About 800 discharges. Not but what it will stand more than that, but we look for about 800. The Ordnance Office has withdrawn them at 500. But we think when a gun has fired 800 rounds it ought to be withdrawn.
12 Nov 1867 Army brevet Major General A. Gillmore
3.Q.What sort of gun had you there in use.
A. All the heavy guns were Parrots; I had field batteries besides.
16. Q. What damaged did it do (8 inch Parrot nicknamed “Swamp Angel”) https://www.battlefields.org/learn/articles/swamp-angel to the city while under your direction?
A. That gun burst after the thirty-sixth round…………………………
18.Q.If it had been perfectly level, how long would it have lasted?
a. It ought to have lasted 300 or 400 rounds; and I judge because the average endurance of his guns is 310 rounds. I have always regarded the form of Mr. Parrot’s large guns as defective.
39. Q. Do you remember how many guns were burst?
A. Including one small gun, a 30 pounder, I burst 23.
A. We mounted and used all the guns sent to us as long as they were serviceable. They either became unserviceable by bursting open or by the muzzle blowing off.
Page 156. It may be remarked that no rifle gun has yet been devised which can be considered perfect, and the bureau has sought in vain among the systems of European nations and the improvements of our own country for a better gun, taken as a whole, than the Parrott rifle. Its life as fixed by the inventor is 750 rounds, but the navy guns have in many instances shown a greater endurance.
Nine large Parrott rifles bust during the Naval bombardments of Fort Fisher. Admiral Porter stated that the Parrott 100 pounders
“were unfit for service, and calculated to kill more of our men than those of the enemy”..
I was unable to find if the service life of the Parrot, as fixed by the inventor, of 750 rounds was the lifetime of all Parrot guns, including the field artillery, or was just the heavy artillery. Considering that the heavy artillery lasted on average, 310 rounds, it does not seem unreasonable that if field artillery lasted 750 rounds, that would be considered quite good in comparison.
3. The Army actually no longer defines the life of artillery tubes by a set number of rounds, but by through a variety of means, that include number and type of rounds fired, actual bore measurements and measured muzzle velocity. The breech (which is not part of the tube) will be inspected with each tube replacement, and reused as condition permits. The life of the gun carriage, by design, is twenty years before requiring an full overhaul which is considerably longer than 15,000 rounds, and the carriage is inspected and repaired as necessary, not scrapped. (And, at 1.2 million a copy, I certainly hope they last longer than 15,000 rounds). However, during development of the XM777 there were problems with metal fatigue in some carriage components, but this has been corrected in the production versions.
My source was a retired cannon designer I met at a match. My memory was that I was asking about the lifetime of the 155 mm. I don't know about your references, but a 20 year lifetime while given for an Army material item, is also bounded by an expected number of miles, rounds, flights, etc. Sort of like a car warranty, X miles for Y years. I do not believe that any 20 years lifetime for any artillery piece assumed an infinite number of rounds, so there must be some failure criteria other than clock time. Maybe it is more than 15,000 rounds, maybe not. If the carriage cost $1.2 million, that seems to be a lot of money, but it is inconsequential for the lifetime medical costs that the services incur with severe trauma survivors.
Somewhere, someone, has done the calculations, where the cost of replacing the items is less than the medical costs of the injuries to be expected. This was not always so. Congress established the Veterans Administration in 1930. There were patchy disability programs starting around 1917, just as America entered WW1. I read that the early agencies were funded separately from the services, which gave a perverse incentive to the services to do things, such as issue single heat treat 03's, which were known to be defective. The cost of replacing a rifle was about $40.00. If the rifle blew up in the hands of a serviceman, another agency had to pay for rehabilitation of the injured out of its budget. Prior to 1917, all the services were obligated to do, was patch the victim up, once they were stabilized and could walk, and the injured party was off Government property, Government support ended. It was very similar to how the NCAA treats inured student players today. So there was a time when the health and life of a US serviceman was worth less than a forty dollar rifle.