Pretty much agree with everything above. However I did have a conversation with the owner of rock creek many years ago and he was talking about making tool steel barrels. He offered to make me one if I would pay for it.
he may not take your blank but he might make you one out of steel he sources
it’s worth a phone call
I would bet not M2, M48 or other HSS.
I don't know why anyone would. Normal barrels are made of 4140, 4150 or 416 stainless, and they are tempered below maximum hardness to improve fracture toughness. And we don't see these losing rifling.
Yes, cobalt, nickel or tungsten tool steels in a harder condition would resist throat erosion better. But at what cost? And then there's the danger of using high hardness alloys that will shatter like glass when their limits are reached.
How materials fail can be just as important as
when they fail, if not moreso. Do they bend, stretch and tear, or do they snap/shatter and turn into shrapnel?
If I were going to make a barrel out of a different alloy with the intent of better throat life, I would use 8620 and do carburized double heat treat on it after chambering. It can achieve >60 Rc case hardness, but has a softer core, so not prone to fracture like through-hardned tool steels. But that, like nitriding internally, is tricky due to dimensional changes and material growth.
But alas, regular old chromoly or 416SS barrels have worked just fine for me.
I think OP got the idea that a harder barrel=better barrel and then googled for the hardest steel alloys and bought a chunk of material in that group that he could find. Unfortunately, he does not seem to have spent the time researching what combination of mechanical properties make certain alloys suitable for barrels and others not at all. Tensile strength and hardness are important mechanical properties, but certainly not the only ones that matter. I wouldn't use tool steels for a suppressor tube for the same reason I wouldn't use them for a barrel. We want pressure vessels to have more moderate hardness with some ductility, and we want the materials to fail in a way that they won't send dozens of razor sharp projectiles in all directions if they do let go.
Also, firing rounds through a barrel made of annealed martensitic or precipitation hardening alloys will not result in hardening. M48 requires a specific multi-step heat treatment process and subsequent tempering.