Trying to get ahead of the curve. It looks like Wa is moving forward with SBR's and when this legislation passes I will setting a rifle up. So I want to understand what is expected and figure this is a great place for some pre-approval education. From my very limited research I have to mark the rifle with my personal info. Does that mean the serialized component ie.. AR lower, Sig 556 upper. I have not decided which way I will go yet but have a number of lowers that could be use for this process one of which currently is used for an ARAK 21. This is an easy system to install a 12.5" barrel on and would be a good candidate. However, I plan to by one of the new Sig XI rifles when they hit the market. This system is suppose to have 10.5" user changeable barrels in 5.56, 300 blk and 7.62. The lower on the rifle has to be changed for the proper magazine to support the fired cal. This seems like the ideal way to have it all; if I have to mark the upper and then could have an SBR in my selected cal and configuration with only having to register one rifle. So the question is will this be legal, thoughts.