If you have a bum round it doesn’t matter what gun you put it in, all slides and barrels are metal and it would have did that to any gun. As for the polymer guns, there are many Glock 17’s with over 500,000 rnds fired from them without any frame breakage, that is a very durable material. And even though the frames are polymer they are reinforced with metal for strenght, just helps in weight reduction.