re: plastic gun parts

In my experience the worst bit of plastic on a rifle was the plastic bottom of the Brno .22 steel magazines. The Brno .22 was one of the firearms of choice in Western Canada for summer shooting of gophers (Richardsons Ground Squirrel)...and Muskol was a good strong insect repellent of choice, necessary because of the clouds of mosquitos. So after successive applications, the mosquito repellent tended to accumulate in the palm of your hand...and when changing magazines with the same palm of your hand...after a time, the plastic would just suddenly disintegrate , releasing spring and ammo into the field somewhere. It wasn't so bad when those mags were cheap, but they aren't anymore. I note that the mags on the new CZ rifles are all plastic.