O-Ring question

So I am wondering about these. I know you can get them for about .01c from McMaster.

What I am wanting to know is why did they choose Viton Fluoroelastomer? It has a hardness of A75 and an operating temp of -15 to +400. Wouldn’t something like Fluorosilicone have been better? It has a hardness of A70, but a much larger operating temperature of -75 to +400.

Color is of course black and blue respectively. So why did they choose the Viton material over the one with the larger operating range, What material does the D-Fender use?

What O ring are you talking about?

Extractor o-ring.

Likely tolerance to petrochemicals and solvents.

Do you happen to have the McMaster Sku?

Sure do…though I was off on the price, they are .10c each…or $5 for 50.

http://www.mcmaster.com/nav/enter.asp?partnum=1201T16

Mil spec Viton 006 o ring.

Thanks, I need some for bench stock.

Are we dealing with water leaks or some shit? If your gun needs an O ring, replace it.