The question of what is a reasonable lifetime is a very important issue. The buyer wants an MTBF of 1,000,000 years with an infinite lifetime, for $20.00. Thirty bucks if the gun is shiny. The manufacturer has very different expectations. Now any darn fool can build a twenty or thirty pound single shot firearm that never breaks, the real art is making one as light as possible.
From what I have read, the early M1911's had to pass a 6,000 round endurance test. To pass a 6,000 round endurance test, obviously the pistol has to be built so all pass this test, which means the pistol will function longer on the average. These numbers probably came from the experience of the military and estimates of a reasonable number of rounds per year. It could have come from the Arsenals and Shooting Teams, where round counts, pistols rebuilt, etc, were considered. I believe a case can be made that the firearm should last as long as the barrel, as barrels typically wear out first. So with the soft steels of the day, after 5000 or 6000 rounds the barrels would be shot out, the pistol send back to Depot for overhaul. Once at Depot any part could be replaced if need be.
Something to note, the early M1911's were made of plain carbon steels and were not even heat treated. Gunsmiths state that the parts are dead soft. By the time WW2 rolls around, from what I have heard, slides and frames are still plain carbon steels but case hardened for wear. They will last a bit longer.
I got to shoot with the All Guard, they are using WW2 era frames, maybe other parts, in their Bullseye Pistols. I talked with the Armorer and forgot all the details other than these slides and frames have to be refitted in time spans equal to years. He had wear criteria and I forgot what it was, I think it was frame rail thickness. Frame rails are peened, then the slide and frame are assembled with a hammer and grinding compound in the slide rails. The slide is beat back and forth till experience says, the fit is just right. Not too tight and not loose at all.
I also talked to the AMU shooters. I asked about pistol durability, etc. Seems their frames and slides were made by Caspian Arms. No one on the firing line knew how old they were other than these things had been around before anyone joined the team. Some guys thought they might have been made in the 1970s or 80's. I talked to the gunsmith David Sams about these pistols, he claims he helped set them up in the middle 1990's.
I asked the AMU shooters how many rounds they shoot through the things, well the AMU shooter said about 5,000 to 7,000 rounds. I asked, "per year"?, no, "per month!"
AMU shooters wore out triggers, sears, in time periods close to a year, if my recollection was right. Barrels took several years. Springs were replaced frequently. No one had ever seen a frame or slide crack or break, and none had every required refitting, within the experience (around six years max) of the shooters on the line. That is just exceptional.
There are a number of differences between vintage M1911's and these modern era pistols. The first is alloy steels. Alloy steels are so superior to the plain carbon steels that were in exclusive use up through WW2 in firearms. When arms manufacturer's first used nickel steel, such as Winchester, they bragged about it. After WW2, even though that was vacuum tube era, everyone knew and understood that the material properties of alloys were so superior that only legacy designs and lazy firearms manufacturers used plain carbon steels in structural elements. In the 1990’s, the semi conductor revolution began to affect manufacturing. CNC machining has produced the tightest factory pistols that have ever been made. Pick up a Kimber, a Range Master, or a Les Baer. They don't rattle. The old Colt series 70's and 80's rattled when new. The combination of better steels, cleaner steels, and better machining have extended the lifetime of firearms, given the same loads.
I have talked to several serious Bullseye shooters who also shot revolvers. One, his custom. 38 Special barrel was still shooting two inch groups at 50 yards with 600,000 rounds through it. The loads he used were 148 LSWC with 2.7 grains Bullseye. This guy had won multiple PPC championships with his K frame S&W. The other shooter had around 250,000 rounds through his S&W K frame revolver. Both said extractor stars wore at some point, their revolvers lost their timing, and they had to send their pistols back to S&W. I think cylinder hands also wore. One guy had a S&W hammer mounted firing pin break. I assume they replaced springs along the way. I was told that Colt revolvers were very rare in PPC as they got out of tune much earlier than the S&W. It had to do with the timing of the lockup. Colts locked up during hammer fall, S&W’s locked up before hammer fall. Colts were much more sensitive to wear in the cylinder hand and extractor star. The PPC champ said that rebarreling a S&W with a Colt barrel was fairly common as the Colt barrels were tighter and shot more accurately. He called the conversions “Smoults”.
Barrels are going to wear out with jacketed bullets. I have no idea of the fatigue life of a barrel, they are a pressure vessel, I expect at some point they will rupture. A low pressure cartridge such as a 45 ACP I expect the barrel will never fatigue rupture before the rifling is worn smooth. However, I am aware of a shooter who had a vintage 30-06 barrel rebored to 35 Whelen. The rifle barrel had gone through its normal service life, was old steel, several ounces had to be removed to enlarge the tube to 358 diameter, making it weaker. The shooter fired a couple of factory 35 Whelen rounds, the barrel burst, and the owner is mad at the barrel maker. The barrel maker blames the owner and ammunition, the owner blames the barrel maker. I don't know the end of this, but the barrel maker is assumed to know more than the customer, but in my opinion, both should have known better. I am of the opinion that once a barrel is shot out, it ought to be replaced with a nice new barrel made from nice new materials.
Incidentally, I recently had my 1960's fire extinguishers recharged. I learned a lot about fire extinguishers, and I am no expert on the things. Fire extinguishers are pressure vessels, they fatigue fracture, I found the example of a guy whose fire extinguisher blew up, was he was carrying it, and he died from the shrapnel.
When fire extinguishers are inspected, how often, and how often they are pressure tested, is a very complicated process. You can look here for times, which depend on a lot of things.
https://www.approvedprotection.com/...fire-extinguisher-maintenance-schedule-guide/
Technician said my fire extinguisher was made to a 5/3 safety factor. If max allowed pressure is 1800 psia, which is probable based on ICC 3AAI 1800 stamping, than a pressure test of 3000 psia corresponds to a safety factor of 5/3.
My fire extinguisher was put into this armored tank which was filled with water. The fire extinguisher is in water at atmospheric pressure. What they do, is they pressurize the fire extinguisher, with water, and measure the amount of water, atmospheric pressure, that leaves the tank.
The pressure test consists of adding water to the fire extinguisher, increasing the pressure to 3000 psia, which is the maximum structural pressure, (remember maximum operating pressure is 1800 psia) and measuring the amount of water that leaves the armored tank, and the amount of water that is drawn back into the tank, when the internal pressure of the fire extinguisher is brought back to ambient. There are pass fail criteria for the amount of expansion allowed, and the amount of contraction allowed.
There is a 35 psia blow out valve on the water tank, to relieve the pressure if a pressurized fire extinguisher fails. If the tank fails, the valve ruptures, and all the water in the tank is blown against a wall. Hopefully sparing the test operator!. Of course, I had to ask, "do fire extinguishers fail?". Why yes, they do.
This is the paint blasted from the wall when fire extinguishers fail their maximum rated pressure test.
You know, if fire extinguishers blow, there is no reason to assume that barrels, which are also pressure vessels, are going to last forever. Barrels carry more of the pressure induced load, than any other structure in a firearm. More of the cartridge case is supported by the barrel, than is supported by the locking mechanism. The guy who paid someone to rebore his 30-06 barrel to 35 Whelen should have had enough sense to have a new barrel installed, but the barrel maker is the one who is assumed to know better. He has the product liability. Manufacturer's are assumed to be expert in these things. Anyone reboring old barrels is taking a risk. You don't know the quality of the old steel, you don't know what loads were fired down the things. Even famous gunwriters should know better: P.O Ackley said no one knew what loads firearms were designed to, therefore it was fine and dandy to fire his non pressure tested loads, (around 80,000, to 90,000 psia) down firearms that were designed for 50,000 psia. Actually, it was Ackley who did not know how firearms were designed, but he has a lot of followers who think he knew what he was talking about.
Bolt action rifles, I have had the bolt cocking cam wear out on a Mauser 98. I used the action as an XTC rifle, it was in 30-06. The thing went through three barrels, and was dry fired tens of thousands of times. Whatever case hardening on the cocking cam wore. After that the firing pin nose galled the cocking cam, the rifle was hard to operate from the shoulder, and so I replaced the bolt.
I had the firing pin cocking nose piece break on a M70 target rifle. It was on its second or third barrel, had been dry fired an ungodly amount. I was able to buy Tubbs M70 parts and the rifle is functional
You can find pictures of cracked bolt lugs on all sorts of actions. All bolt actions, and semi auto’s will crack lugs in time. The lugs on a AR15 typically start cracking lugs between 10,000 and 30,000 rounds. The better made AR15 bolts will last 30,000 rounds before cracking. Depends on the materials and heat treatment.
