"Steel" covers a lot of territory. For plain carbon (not enough other alloy elements to be a significant factor) steel, low carbon steel is pretty soft and high carbon steel can be quite hard with proper heat treatment. Adding in some of the "usual suspects" such as silicon, copper, lead, tungsten, chromium, nickle, sulfur, moly, etc. and you can change the properties a lot. However, carbon remains very important. Well case hardened low carbon steel makes perfectly satisfactory gun frames and levers. Properly hardened high carbon steel makes fine springs. Plain low carbon steel is just fine for barrels. So, plain carbon steel technology is good enough for guns, even though modern alloys are better.
Tests by the Birmingham proof house found the best of damascus barrels to be a little stronger than early fluid compressed steel (low carbon). Both were strong enough to be made into barrels with walls thin enough that denting was much more an issue than bursting.
Plain carbon steel technology was fairly well understood by the British and dramatic progress was made in quality in the late 1800's. The major advantage of modern steel is in both quality of cleanness and in specialized alloys.
There are no "lost secrets" of steel. The original Bowie knife was reputed to have had some meteriorite - likely some good alloy elements in there. True Damascus, not the laminite we use for gun barrels, was based on some stuff called Wutz and has been recreated. It is much better for cutting edges than plain low carbon steel, but nothing special when compared to modern blade technology. Had you been armed with a low carbon steel blade, and your opponent armed with Damascus, you might very well have considered his sword magical. However, most of the magic of ancient steel was based on one-time fortuitus alloying and was not generally repeatable on demand. Characteristics were all over the map.
