Grads, Katushas, Kalashnikovs, rpg-7s, IEDs.

None of their popular weapons are hard to DIY. 

Some of their limited stock of anti-tank missiles may be factory built (Kornets), but those are widely proliferated and made in Russia. 

 Hamas builds their own rocket propelled grenades and anti-tank missiles, and morter launchers out of plumbing pipes. They have some US made weapons from Afghanistan and Ukraine. But mostly the imported weapons are of Soviet manufacture that are claimed to have been modified by Iran. They also copy weapons: Their Shabab drone is a copy of the Iranian Ababil-2. I think they take any weapons they can get, and most of the world is behind them so they get weapons from all sorts of places, including Russia and Iran. I"ve heard they have some from North Korea and China too. 

 ^ This 

 Yes they have a common enemy and put aside their ideological differences. I guess I was wrong. 

 I didn't even read the article or care for either side. I'm just commenting on your initial post about westerners not understanding Islam. Sometimes ideologies are irrelevant when you have a common enemy. Apparently it's seems less plausible to you guys that Iran and other Islamic adversaries would be supplying the insurgency rather than Russia and North Korea. Hell even China. In the same argument why are the Shias attacking Israel at all if they don't care about the Sunnis?