Wildcat .25 cal breech o-ring size

Get it from the source:

http://www.fxairguns.com/wp-content/uploads/2015/10/wild-exploded-drawing-AoA.pdf

Thurmond

6.35 x 1.27 mm. I've looked everywhere online and only found places overseas. So I just ordered some from AOA. Keep us posted if you find another source. Thanks , Eddie.