Ken, I am not convinced by the argument of the superior ferry range although both ac have the option of receiving fuel to increase their range. I would agree that the AAR equipment fit of the 767 is better ie all 3 hoses and a boom but at the end of the day I guess the USAF would just like a new ac soon. This replacement ac was supposed to have been in service a long time ago.
Keep in mind that ferry range is range with max fuel and zero payload, with no inflight refueling. All airplanes (generally) are designed to carry a payload, they can never reach max takeoff weight with just fuel. At max fuel they always have some take off gross weight margin which is used for carrying a payload. The inverse is (generally) also true. When loaded with their maximum payload, they cannot carry a full fuel load.
This results in two "knees" in the payload/range curve of (virtually) every aircraft.
The first knee occurs when the aircraft has at maximum payload and is then filled with fuel to its max takeoff weight. The curve slopes down to the right, with each pound of payload taken off compensated by a pound of fuel added. The second knee occurs when the aircraft reaches it's fuel volume limit. At that point removing a pound of payload cannot be compensated by a pound of additional fuel. The curve slopes down much more steeply, with the range increase resulting only from the lower gross weight of the aircraft.
The 767 and A330 are designed this way. Both carry fuel only in their wings. When they reach their fuel volume limit, they still have significant gross takeoff weight margin to carry passengers and cargo.
The MRTT, like the A330, carries all its fuel in its wings. It cannot trade payload for additional fuel.
The KC-46 has belly tanks. It can trade payload for additional fuel in those belly tanks. Basically, the belly tanks move the second knee in the payload/range curve to the right.
The result is that the KC-46 has a ferry range advantage over the MRTT. This also means that MRTT has a payload advantage over the KC-46 when each are loaded with max fuel. But USAF did not prioritize cargo capacity when these tankers are full of fuel for a tanker mission. Why? Basically because USAF uses the KC-135s and KC-46s as EITHER a tanker, OR a transport, not both simultaneously. USAF uses their larger KC-10s as BOTH a transport and a tanker on the same mission. For example, when deploying a fighter squadron the KC-10 carries support equipment for the fighters at their deployment base, as well as providing fuel to the fighters enroute to their deployment base. Once forward deployed, the smaller KC-135s and KC-46s provide tanking services in the theater. USAF has the luxury of a mixed fleet of tankers which are optimized for different employment scenarios. Which also makes USAF's procurement decisions different than other nations' procurement decisions.
BTW, returning to the subject of size. Boeing could have offered a KC-46 with the -200 fuselage and the wings and landing gear of the -400ER, instead of the -300ER, making up much of the A330's advantages. Why didn't they? Because then their offer would have lost its advantage in MOG and MILCON.
And oh yes. USAF has announced where the first KC-46 squadrons will be based and where the KC-46 "school house" will be based. McConnell and Altus were chosen because these bases required the least MILCON to accomodate the new aircraft.
And finally, the AAR equipment of the KC-45 and KC-46 were essentially the same, with 3 drogues and 1 boom. And after an expensive redesign of the boom by Boeing, the two booms had essentially the same performance.