Handloader for .50BMG... Good luck with that. I have one of the RCBS AmmoMaster presses. That monster has a HUGE mechanical advantage built into the lever/ram mechanics. Even so, it is a workout sizing brass. Unless your name is Dr. Bruce Banner, Forget about a hand loader for .50BMG and move on... I doubt such a creation would even work for 1% of the population. The forces needed to set back the shoulder on that case are well beyond the grip strength of most mortals and even a few demi-gods!!! Frankly, the $500+ the AmmoMaster set me back years ago was money well spent! Although I don't use it for anything other than the BMG. A slightly askew 30/06 will be destroyed before you can even feel the resistance on the lever.
Just make sure you mount it to a sturdy and VERY heavy bench. Again the force required to size .50BMG is huge! If the bench is not heavy enough you will move the bench before you size the brass.