Good grief, this did help on my Tau 7, after several lost C02 bulbs, it did not leak. I had been applying a smear of oil (as I had read on other threads for the Tau 7), but that did not help. Amazed that vaseline did the job. As mentioned above, the user guide on the Pilkguns website refers to a slight amount of silicone grease on the o-ring in the piercing cap and on the bevel inside the chamber.