No, contrary to the reports being spread, the Czech Republic has not yet delivered 300,000 artillery shells to Ukraine.
Jan Lipavský, said it had so far secured 300,000 shells and that the ammunition would provide a vital few months breathing space on the frontline, while sources added that the first deliveries would come before June.
https://www.theguardian.com/world/live/2024/mar/20/russia-ukraine-war-live-france-calls-russias-remarks-on-troops-disinformation-and-irresponsible?page=with:block-65fab6418f086c822f2141b1&filterKeyEvents=false#liveblog-navigation