He spent hours working on the catalyst, which has very specific kills you need to get (that whole 'burning an enemy to death' thing he was trying - too little health to start with, they die from the bullet, doesn't count, too MUCH health to start with, they survive the explosion. It takes a lot of precision to get a LOT of kills, which you need to masterwork the weapon.

But if you do all that work before you actually apply the catalyst to the weapon and BEGIN the masterwork process... you get zero progress. The VERY FIRST THING you have to do is apply the catalyst. Which he didn't do.