Hi Dave
First off do not take this as any kind of personal attack.
It is very difficult sometimes to get points across in print without seeming abrupt, rude etc etc.
I may be blunt and sometimes
I go on rants. But bear with here.
On the subject of work hardening. Yes it is written that it requires plastic deformation.
But how do we explain the term "fatigue life" which does not require plastic deformation of the material to produce failure? I think this is what occurred in the Remington shotguns. Why do I mention Remington shotguns? The stuff I read sometime back and of course can't find on the WWW anymore, detailed what I was trying to get across. It was well researched and seemed to be conclusive. Remingtons legal team was not able to refute the explanation. The class action stuff is more available and does not say the same things I recall from the personal injury case.
The White Lab report on the blown Indian made musket was a joke in comparison. They were paid to find a mechanism for bursting the barrel, which they did, apparently they were not paid to do any metallurgy.... But some people gleefully quote this as proving that DOM tubing is safe for musket barrels. I read the report, what was released to the public anyway and had more questions after reading it than before.
Using a material that is already brittle or that will become brittle or that usually has built in flaws like tubing can easily can cause problems. All cold drawn steels are brittle and most are brittle at room temperature. This means they tend to burst before deforming, but not all the time. Sometimes nitro propellants will produce brittle fracture in materials that are not supposed to be brittle. Isn't this fun?? Except for certain underload and overload scenarios with smokeless powder blowups are often impossible to recreate. A barrel fails and then an identical or even thinner wall barrel of the same material simply cannot be blown or even significantly bulged. But why did the barrel blow? "Had to be loading error" but the shoot is adamant that it was not?
? Now we get back to the "whose fault was it" and like unexplained airplane crashed its gets blamed on the "pilot in command".
How about "hoop strength", a materials ability to tolerate internal pressure.
Some materials that work very well for some applications have far different characteristics when internal pressure is applied and this invariably gets worse when the pressure rises rapidly as in firearms barrels.
Pressure inside the barrel goes from atmospheric to 10000 to 60000 psi plus or minus 1/1000 of a second.
Since you have access to metallurgists see if they can tell you about fatigue life and why the Remington barrels failed. Ask they have looked into firearms failures or if they know colleagues who have.
Really.
As a gunsmith or manufacturer it can be tough to get a metallurgist to get into the subject of burst barrels. When it comes from the firearms industry metallurgists, in my experience, tend to "duck and cover" to avoid being called to testify in some lawsuit. The last word I got concerning barrel steels came from a professor of metallurgy via an email from the prof to a friend of a friend so I did not even know the guys name, and it simply stated "why would anyone use anything but chrome-moly for gun barrels". I had asked about using "stress proof" as BL gun barrels and that was all the answer I got. Of course there were other answers as well. But the guy I got the sentence long comment from was not being paid by anyone to give an opinion.
So if you can do it see if you can get your colleagues to do a little research and give an opinion. I see this as an opportunity. I have many questions. For example, how is it that in some barrel failures the split in the barrel progresses faster than the bullet is traveling and parts of the bullet are left in the crack? Why do some barrels break and others just bulge?
So far as ML barrels etc. I know barrel makers, people who run firearms companies etc etc. Back in the 1970s early 80s it seems like John Baird got a report on every blown up ML that any subscriber heard about. There were quite a few actually and not all were "explainable". There were failures, for example, of Douglas barrels, at least 2 splitting at the breech with service charges and another Douglas barrel with serious bore obstruction that simply bulged. I have a photo of a sectioned bulged barrel someplace that I scanned out of an old Buckskin Report. The barrel simply bulged at the location of the ball that went down about 8" and stopped, there was heat related discoloration at that point but no cracks. The owner got P.O.ed and shot it out of a very expensive rifle which, since the barrel did not break, survived to be sent back to the maker and rebarreled.
I know a man who likely makes more barrels in a year than the US ML barrel industry does combined. But I can't quote him on this website without being attacked.
The scary part is the things that can be "gotten away with". A ML gunsmith in the town I live in (there used to be 2 at least in the 1970s) had a caplock import brought in to him because it was misfiring. This particular pipe bomb has a drum screwed into the barrel that looks like a small bolster. The smith disassembled the gun and in removing the drum it turned about 1/4 turn and FELL OUT. Yet it withstood a range session. So when I see a post or hear a comment about some wonderful thing they have bought or made in such & such a manner (like they did it in the old days perhaps) or out of this or that material and that its safe since it has not blown up I silently add "yet".
I don't make statements about safety off the top of my head. I actually do have some background.
I fully understand the "idiot factor". But I also know there are a LOT of guns out there, vintage, new ML and "reproduction" breechloaders that are just waiting for that "special" stacking of circumstances to hurt someone.
I examined a rifle used in cowboy action shooting that spit out parts, with no barrel damage BTW, that cost a shooter his eye and came within a hare's breath of killing him. Was it his fault? Sure. He was trying to blame the manufacturer. He had a couple of gunsmiths who agreed with him. I did not, it was impossible for the scenario to have gone as he was proposing, the gun could not be made to do it. Surely did not make him happy but shortly after I published my opinion on this I walked into a gunsmiths shop in the city he lives in and the owner came out of the office with a photocopy of the article, congratulated me and then pulled a broken SA colt copy out of drawer and said "same guy".
HOWEVER, the rifle design he was shooting is NOT SAFE WITH SMOKELESS POWDER in my opinion. Why? It has no safety features. Had he been shooting a copy of design from a few years later, in the 1880s, I will call them second generation lever actions, he would have likely suffered no injury at all to gun or shooter. But the "first gen" guns are EXTREMELY reliable at high speeds and the CAS competitors use a lot of them for this reason. So these things are made in quantity in Italy some even with brass frames.
Now we run into MLs.
We have people shooting blanks in import muskets and bursting them with "bore obstructions". We have virulently corrosive propellants and low end MLs with fouling traps that keep the corrosive fouling in contact with the steel where it eats "crawdad holes" in breeches. I have seen PHOTOS this is not supposition plus a European national proof house telling a resident of that country virtually the same thing. But if you post it on a web site some "expert" will at least infer you are an idiot. Never mind my years of looking at ruined bores in virtually new guns while guns used with BP suffered no ill effects, research by people who have spent years looking at BP and replicas powders, this is all "impossible" to someone who has not spent 5 minutes researching the topic.
So forgive me. I have grown somewhat skeptical and probably even dismissive of many things I read.
But do see what information can be gleaned from the metallurgists. But ask them to take some time and LOOK not just answer off the top of their heads because firearms, frankly, are not rocket science. The pressure is high, there is very rapid pressure rise and this does make a difference as to how materials react.
Wind is down need to go shoot.
Dan
