if you need the entire length of an extruded part to have a precisely finished bore, you will probably have to draw over a mandrel, which will swage the inner surface. A cutter head can also be drawn or pushed thru. This is where a really good toolgrinding shop can save you some headache, rather than experimenting. On a diecasting, if the bore depth is not too deep in relation to the size of your ellipse, you could just machine these on a machining center or even jig grind them, depending on your surface finish requirement.
