I got the auto rifle and then done the 4th forge and done the max temper my friends done that and it dropped first time. When I done that I also had it drop on the first go try that. BTW I know people will say that's not true it happened for them and me maybe you can try it
I've been doing max temper every time, in every forge hoping it would increase my chances for something awesome, but no such luck.
Needs to be the last forge for Jotun and get the auto rifle also