User blog comment:Jar teh marksman/Map Pack idea?/@comment-124.82.9.219-20110317092107/@comment-32136229-20110319055306

Well, the machine will only allow 10 weapons to be used for combination process, which you have to pick two of them that you wanted to combine. The reason for ten weapons is because there is other weapons that are not suitable to be upgraded with another, and to save spaces. So, I'm gonna keep it to 10 weapons.