It's not as if this is some mystery that hasn't been reported on. Hamas brought them in through its tunnel network that crosses the border with Egypt, by sea, concealed in the import of other goods, and by making them locally with Iran's assistance.
How does Hamas get its weapons? A mix of improvisation, resourcefulness and a key overseas benefactor
The Iran factor
“Hamas acquires its weapons through smuggling or local construction and receives some military support from Iran,” the CIA’s World Factbook says.
While the Israeli and US governments have yet to find any direct role by Iran in last weekend’s raids, experts say the Islamic Republic has long been* *Hamas’ main military supporter, smuggling weapons into the enclave through clandestine cross-border tunnels or boats that have escaped the Mediterranean blockade.
“Hamas’ tunnel infrastructure is still massive despite Israel and Egypt regularly degrading it,” said Bilal Saab, senior fellow and director of the Defense and Security Program at the Middle East Institute (MEI) in Washington.
“Hamas has received arms from Iran smuggled into the (Gaza) Strip via tunnels. This often included longer-range systems,” said Daniel Byman, a senior fellow with the Transnational Threats Project at the Center for Strategic and International Studies (CSIS).
“Iran has also been shipping Hamas its more advanced … ballistic missiles via sea, in components for construction in Gaza,” said Charles Lister, senior fellow at the MEI.
But Iran has been a mentor, too, analysts say.
“Iran also helped Hamas with its indigenous manufacturing, enabling Hamas to create its own arsenals,” said Byman at the CSIS.
A senior Hamas official based in Lebanon gave details of the Hamas’ weapons manufacturing in an edited interview with Russia Today’s Arabic-news channel RTArabic published on their website on Sunday.
“We have local factories for everything, for rockets with ranges of 250 km, for 160 km, 80km, and 10 km. We have factories for mortars and their shells. … We have factories for Kalashnikovs (rifles) and their bullets. We’re manufacturing the bullets with permission from the Russians. We’re building it in Gaza,” Ali Baraka, head of Hamas National Relations Abroad, is quoted as saying.