Karn is such a great commander, always good to see what others are doing with him. Out of interest do you not find yourself flooded bearing in mind how many excellent colourless rocks there are, the fact that there are no ways to ramp out more than one land a turn and that one is just a dead draw later in the game? In mine A Gathering of Golems I only run 25 - which I admit is pretty edgy - but 40 is more than I'd put in a normal multicoloured EDH deck. Even straight swapping five for more rocks or creatures that tap for mana would synergise more with any "artifact matter" cards and can be animated to swing for damage in a pinch. I reckon Voltaic Construct and Golem Artisan are essential Karn picks as well. Sounds like you got lucky at the pre-release too, I'd be jealous but I got an Ugin so can't complain!

loricatuslupus I do find that i get flooded occasionally, however in my meta mostly landburn became major because i cant help myself with infect. so no with karn i find that that is still a threat and i take alot of focus. i find that when i when with this it is mostly because my lands allow me to keep going while holding a few in my hand to fake like i might have something. tho i will be looking too cut some once i get a Metalworker and a few other key ramp cards. thanks for checking it out ill definitely take a look at your deck