I just came in from the shop. making a part out of UHMW, a long chain polymer that is common in industry.
I took a .130" deep cleanup cut from the outside diameter in the lathe and saw deep checkering even deeper than that. The 6" diameter UHMW bar is maybe ten years old and doubtless absorbed some UV's.
But the real point is that I expected it before taking off the .130", plastics outgas and are degraded by UV's, and this had been stored in a outbuilding that had overhead fiberglass panels so we wouldn't need lights out there. Daylight attacks many plastics.
Had the original customer who I purchased the UHMW for called for black material it probably wouldn't have checked so deep, but that would not effect outgassing.
Now they are going to need to start making more guns with all the plastic they can't make straws with.
You like "polymer"? Good for you. Enjoy what you like and stand up for it. Steel has problems too, as does 416 stainless, just different, and in my opinion less dissipating problems.
By the way, I program CNC's in my shop, and hire operators to run them, and while it's true that certain operator spots don't require too much training most of them need a great deal more intensity and watchfulness than most plastic assembly lines do, as the material is generally more expensive and a poor operator can drive one into red ink fast!
A good operator needs to use many measuring tools and meet many observational requirements, when a part begins to grow a few tenths he needs to know how to adjust the offsets, and know when a tool needs changing, another potential challenge. It does take a good deal of skill to operate a CNC mill or lathe and do it right.
In my opinion the movement towards more and more plastics is caused by the same motivation behind zinc alloy guns parts, a quick buck.
As for me. I carry a Kel tec, but it's an entirely different feeling for me, it's a throw away gun straight up. A plastic straw. It didn't cost much and stays out of the sun.
The only thing I have against affordable plastic guns is that manufacturer's aren't making as many steel guns.