Unsure if this is the proper category for this post, but it feels relevant as it is a more technical topic. I was wondering if anyone could shed more light on how to test plastics at home with common household items in an attempt to identify and/or categorize them. I have watched this video a couple times: It provides a great starting point for this topic, but still lacks some clarity and completeness. I have recently opened up a a teammate's RIF to find this piston cracked at the back after one month of use. https://www.evike.com/products/31699/ I will discuss the failure more in my "Tech Log" thread as there were a few things going on that I feel could have contributed to this, including either bad design of the piston, and/or a deformity, but also some custom modifications and other aftermarket parts. I am very certain it is not polycarbonate, but there is some added texturing to the body that appears to somewhat mimic the appearance of polycarbonate. Point of failure: In the second image you can see to the left of the tooth rack there appears to be some missing material. I am unsure if this was part of the damage or if this is a deformity. The plastic is very difficult to break or deform with a single pair of pliers. Deformation and breakage testing: Flame/Melt test: Held a small blue flame easily and did not char. Just kind of deformed and holds its new shape well after cooling off. Produced a good bit of smoke after blowing out the flame. Smell was a bit difficult to pick up on. Very faint. Possibly like burnt electronics as Maekiii describes polyacetal in the above YouTube video. I believe this to be polyacetal. Thoughts?