The B&T APC has forged upper (someone correct me if wrong on this) and poly lower and that thing is CRAZY expensive, and the upper is not even monolithic!
I'll be VERY much impressed if HK can do that and yet still make it cheaper than the 416.
EDIT: Well, looking back a few pages, it looks like Jim confirmed that the upper is indeed extruded.
The upper looks extruded. That said, why would it need a different manufacturing process? The bolt will run on steel inserts, the upper is just there as rigid shell to avoid shift of POI and heat not dissipating away when going "hot", like the "g36 Thermos effect". For that, you dont need expensive forging and that will not in any way improve the quality of the firearm.
I don't know that it does make sense to extrude the upper . You have features on the outside of the Upper that aren't flat and have multiple different radii . Look at your AR upper forging . You don't have much machining where the forward assist , the case deflector and where the cam pin cutout is . You do have light surfacing .
You have the case deflector on the right side that would add material to an extrusion . Are they going to extrude the bore ? Sometimes it's better to start a hole . HK knows forgings as well as anybody . Look at your USP slides , MR Uppers and Lowers , etc . The Upper is where all the geometry is . BTW , anybody can make a lower . As far as the size of the forging ? That's not an issue at all , especially in Europe .
Is it cheaper to extrude vs forge ? Maybe , maybe not . It's probably going to be a preference on what technology HK feels better working with . A lot of the cost reduction is getting rid of the buffer system .