One problem with 12L14 is when you cold draw it, occasionally you get cracks. Back in the 1980's I called Bethlehem Steel's research lab looking for toughness data on 12L14. This was shortly after I learned the rifles which I had made mostly used 12L14 barrels. Knew it was bad stuff but not how bad. Told the metallurgist at Bethlehem WHY I wanted this data, so as not to blind side him with his own information. Told him people made rifle barrels of 12L14. All I heard then from his end was laughter.
Oh.
He gave me the data, then told me the reason Bethlehem had this data. When the grade is cold drawn it can crack, which renders that bar scrap. Quite unprofitable. All machining bar is cold drawn to get that bar round enough to fit in the collet of an automatic screw machine.
Douglas barrels, or so I understand, were further cold drawn into the octagonal shape, so the flats needn't be machined from round bar.
The law firm involved in the suit coincident with Douglas going out of that business was Kassly Bone & Whoever, Belleville, Illinois. I might have some paperwork on this in the basement. The lawsuit was settled, at least metallurgically I think, because the Professor (not me) involved found many small cracks in the barrel. I saw one piece of that barrel which someone found later, clearly there was a long seam/crack in the barrel where it blew.
If the steel bar is not cracked, one can load the Devil out of a 12L14 barrel without it bursting. But those few barrels with cracks are likely to one day, and completely unpredictably, do something you don't want.
Y'all wanna send me an in-house email, with your real email, & I can send a pdf of the three-part article on this Muzzle Blasts was kind enough to publish in 1985. Or, just a short piece by the late Roy Keeler, December 1972, showing results of first shot with a particular barrel (no blood shed).
Oh, yeah, them there good ol' hand forged barrels. At Harpers Ferry up to 40% of them failed proof. See
Harper’s Ferry and the New Technology, Merritt Roe Smith. This little .26 caliber, 15/16" barrel had a seam or crack near the breech, which someone years ago brazed together. Brass turns into green stuff when around sulfur long enough. No one was hurt. Maxine Moss lent me this one.