I should've clarified, the nut on my 112 is actually slotted but I was just wondering
why the use of a nut for assembly, especially if it is actually a separate component from the barrel itself.
I guess at the factory level it allows for easy headspacing and then the barrel is stamped after the barrel is set and the nut tight...
After it leaves the factory it somewhat allows the owner to change pre threaded and chambered barrels... it is supposed to be easy but sometimes requires 3 tools - a barrel wrench, and action wrench and a nut wrench... while a normal shouldered threaded and chambered barrel only requires a barrel wrench and an action wrench.