Heath74 once bubbled...
Heavy weight Nylon as used in weight belts and BPs has a break strength of 2,000 lb. per square inch. Heavy weight Polypro has 3,000 lb. per square inch.
Nylon has a higher abrasion level than Polypro.
I think that's abrasion *resistance*... there's a reason our caving rope sheaths are made of braided nylon instead of polypro.
Typical 2" nylon webbing, from my sources, is generally rated between 5,000 and 7,000 lb break strength.
All of my webbing suppliers are saying that 2" polypro webbing has between 600 and 1200 lb break strength. I'm curious about this 3,000 lb figure, especially since I know that nylon is a stronger fiber than polypro. Rope with a nylon core is pretty much always used for life support.. several rope manufacturers make a nylon core rope sheathed with braided polypro, or an all polypro rope, for [budget] water rescue use (spectra is the fiber of choice for this)... but these are typically < 10mm ropes with breaking strengths on the order of 1,000 pounds. This is not at all useful for life support, and a nylon core 10mm rope has a breaking strength closer to 8,000 lb (which is marginal).
I own lots of both nylon and polypro webbing... the polypro, in general, feels a little bit more flexible, but it's also much more "plasticy" and prickly than the cheapest nylon webbing. High quality nylon webbing is far more flexible and softer than polypro.