The Syrian opposition captured some chemical Volcano rockets, without Sarin, which was then provided to the opposition by Turkey, or Perfect replicas of chemical Volcano rockets used by the Syrian government were recreated by the Syrian opposition or Turkish government. As for point one; the Syrian government has never claimed any of their chemical weapons have been captured by the Syrian opposition, even when required to do so by the OPCW. There's also a question of quantity; so far I've collected images of at least 8 Volcano rockets used on August 21st, and there are reports that over 12 Volcano rockets were used. It's been calculated the warheads would have a capacity of 50-60 litres, making for at least 400 to 720 litres of the Sarin mixture. Considering the seriousness of the charges he's making against the Turkish government, such an oversight seems highly irresponsible for a journalist of Hersh's reputation.