From an engineering stand-point, investment cast slides should be fine; in the recent past some manufactures have been making sintered metal receiver components; again, theoreticaly, done right, should be OK, but in practice, it is a different story.
Forging levels the playing field, in that if you use good steel, the pressure aligns and compresses the grain to conform to the shape. Nork uses high tensile steel (someone claims recycled train track rails), and any gunsmith will tell you that their steel is so tough it it hard on carbid tools. This explains the machining marks that some claim is a singn of poor quality; it is actually a sign of very high quality steel.
