You should check with Leupold on the construction of VXIII scope with the 30 mm tube. The reason I say this, is I had the 3-9 x 50 mm Euro model with the 30 mm tube and the internal part were the same as the 1” tube ( info I received from Leupold). They had made the 30 mm tube for European market and I’m not sure if this still applies on the internal parts. Personally I would get the 1” tube unless I was going to do long distance shooting...