Oring help

Did you use the FX parts diagram to get the sizes from? If so, FX uses the inner diameter as the first number and the o ring cross section thickness(or just call it o ring thickness) as the second number. At least FX does on the Wildcat.

I shop for O rings exclusively from oringsandmore.com also, and the way they call out the sizes matches up with how FX does it- 1st number inner diameter and second number the thickness. Where do you think you went wrong?



Anytime someone gives me o ring sizes(wether a fellow forum member or even a vendor of o rings), the most important thing I need clarified is if the first number called out is either the inner diameter or the outer diameter. 

I am having a similar problem. The parts list for the impact barrel and shroud, detail A3, calls for 2) 10 x 2 NBR 70 O-rings. I bought two of that size locally and they don't fit. They won't fit in the rear block without tearing. One of the old O-rings looks to be only 1.5mm thick rather than 2mm. I'm confident of the size of the O-rings I purchased, but I am uncertain of the durometer. Has anyone experienced this before?

A gentleman at FX USA just called me back and told me what my problem is. I have a .30 caliber which does use two different sizes. One is a 10mm x 2mm while the other is 

11mm x 1.5mm. The other calibers use two 10mm x 2mm as detailed in the drawing. Hopefully this can help someone else.