Mr. Glock:
Given the proliferation of mini-magnums - for example, the S&W M19 of the 60's is essentially a .38Spl with one heck of a cylinder upgrade (and they didn't really bother to change much else - the forcing cone is shortened to allow for the longer cylinder!) - my guess is that the steels are incrementally getting better over time. You can make 'em lighter that way, too, without necessarily getting into exotic metals and difficult machining issues.
The plastic folks, IMHO, are moving the same way, but I don't think that there have been materials changes over the short term to match what's happened to steels since say 1900....
ALSO, somebody mentioned that "Glock hasn't kept up" or something like that. A mold for a grip,for example, could cost way over $30,000, and once you get one that is tuned to work with the plastic you've chosen to use, odds are that the next choice in plastic will NOT flow the same way, or otherwise "work" in the existing mold. There's little incentive to re-do a mold until the old one works out.
However, mold design is a bit of a black art (I worked for a plastics plant for more than 30 years - mostly in the office, but picked up a lot by osmosis), and it's possible that the existing molds were created by CNC milling machines, and cutting a new one from the existing program (and then letting a skilled mold maker tune it) would be a lot cheaper than making a new mold for a different material. If the whole job was done by hand (not unusual when I was in the business), the cost would be easily a LOT more, new material or not.... They'll wait for the "(M)" version
....
My "history" is kind of eclectic. Mom's brothers owned a plastics extrusion plant and a molding plant. We later added a pile weatherstrip plant in SC. I started in Shipping at the extrusion plant, moved into the office, did QC and design work for a couple years, and then got into computers. I got into the rent-a-cop business about the same time, as well as telcom. Doing the design work, way back when, I learned a lot about how to design extrusion dies and molds for injection work. Extruding plastics are a lot like the way toothpaste comes out of a tube - but you'll note that the glob coming out often is slightly larger than the hole. That's called "swell", and figuring it depends on the material, molding or extrusion temperatures, and a few other things. It's pretty much a black art, as I said before. Extrusions are easy, btw. I designed more than a few, but we had die makers who knew how to take my figures and make things work. Nobody ever complained.... I did mention being armed?
Anyway, the Glock folks probably won't muck with what's working right now.
Sorry to write my usual novel
.... BTW, with one exception, if you're concerned about MIM issues, the process is exactly the same - including the "swell" and other things. MIM parts are cooked after molding, which causes the metal in the mix to come together and burn off the "matrix" - some plastic. Since you can do all kinds of magic when molding plastics, most of that is also possible with MIM. Calculating what'll happen by the time the parts are ready to paint has to be right up there with predicting the weather....
I now yield the floor to the guys who are young enough to remember this stuff....
Regards,