Quote Originally Posted by Aimstraight View Post
I tried the new spare piercing cap for the Tau 7 (which came with an o-ring fitted)....tightened up the piercing cap....all seemed fine....then all the gas p1$$ed out again!

Not happy with this situation, two piercing caps, apparently the correct o-rings, but all have wasted the gas from numerous 12gm Co2 bulbs of various manufacture. The seal blows out and distorts, they are just not holding the C02 pressure. I shall be looking for an alternative, either a greater radial thickness of seal, or a more rigid seal material (e.g. polyurethane).
Try googleing Tau 7 O rings look for a .pdf from www.luchbuks.net he maintains Tau 7's for the MIT in the USA where they have problems getting the right size O rings and he lists a full set of alternatives for all Tau 7 O Rings. Best of luck, could not post a link for you.