I have a booklet here somewhere called "The Destructive Proof Testing Of M-L barrels" by a man named Cunningham, I think. He was manufacturing barrels at the time, can't remember the Company. He went to great lengths to try and destroy a bunch oof M-L barrels. These were the "dangerous" 12L14 barrels. He did some insane things to them, super, super, overloads , double and triple balls, multiple balls., placing multipole balls spaced apart. cutting deep dove tails, grooves and such and he had one heck of a time getting these barrels to fail even with those insane loads. ...Lk
Cunningham was a barrel maker that made 12L14 barrels what would expect him to write? Not a metallurgist or even a steel maker. Jim Kelly (a metallurgist and ML shooter) wrote articles on barrel steels in the old Buckskin Report magazine and Cunningham wrote rebuttals. Yes any modern steel will, in theory generally, withstand BP pressures, especially if you believe the “tenisile” numbers for some of the cold rolled steels. BUT these numbers are irrelevant when the steel is SHOCK LOADED, or is used to contain INTERNAL PRESSURE. And firearms barrels are subjected to both. Combine this with the internal FLAWS that are endemic to cold rolled free machining steels and you have a barrel that is not safe shock loading alone, according the Jim Kelly, reduces 12L14 tensile to almost nothing . If the steel maker that MAKES these steels, 12L14 IIRC was called “fatigue proof”, by LaSalle steel, states IN PRINT that it should not be used for gun barrels what is one to think?
Here is an example sorry its in reverse order.
LaSalle Steel got into the discussion too….
So if you have a collection of “The Buckskin Report” from 1981-1982 maybe even 1983, you should have most if not all of the articles.
There are photos and text of blown MLs in various issues.
People like to believe the makers of 12L14 barrels and the reference to Cunningham is laughable. You can get a 20 ft bar of 12L14 and make 5-6 barrels from it and ALL may be without failure OR you might have one that will fail for no apparent reason in the first few firings or after years of use. And as I stated again the victim in a ML barrel failure cannot prove that it was correctly loaded. This is how they get by in using a substandard stee.
The other reason. Better grade steels, like gun barrel quality, have to be bought in furnace melt quantities and few ML barrel makers can afford this. To get it requires them to pool orders to get the tonnage up. THEN its a LOT harder to machine, being a hot rolled alloy not crowded with contaminants to make it free machining, cuts are done slower, tool wear is greater and its a LOT harder to cut rifle smoothly as well and it may be necessary to incorporate a lapping operation to bring them to an acceptable finish. Especially the 4140-4150 alloys. And this jumps up the price. Since the alloy is a lot more expensive, it wears the tooling more and is a lot harder to ream smoothly and cut smooth grooves in. A barrel maker I used to buy BRCR barrels from got a military contract for 50 BMG barrels. He told me that if inspectors came into his plant and found ONE bar of steel of an alloy not specified in the contract the contract was instantly voild and not payments for work done paid. Green Mountain got a contract for M4 or M16 barrels years ago and stopped making ML barrels from 1137 as a result at least until the contact was fulfilled. The Remington fiasco with 1144(M for “modified’) shotgun barrels. Cost them a LOT when the WORK HARDENING steel work hardened, became brittle, burst and people were hurt. Shotgun barrels tend to flex when fired, thin walls ect. And while it is way stronger than needed for shotguns if it gets word hardened and becomes brittle it can fail and it did in a number or cases, shooters were maimed There is WAY, WAY more to this than most people think or want to believe. Including RECALLS of firearms.
