Hamas, the Palestinian terrorist group that runs Gaza, is having supply problems. And the Israelis want to keep it that way. Hamas wants to bring in longer range rockets, with larger warheads. These have to be broken down so that they can fit into the smuggling tunnels that go under the Egyptian border with Gaza. But first, those rocket parts have to be smuggled into Egypt. Israel and Egypt are interfering with both operations. No one will say how successful, but there's no indication, or claim by Hamas, that the big rockets are in Gaza and ready to fire.
The fighting last December-January, between Israel and Hamas, was particularly disappointing for the Iranians, partly because of the poor use of longer range rockets by Hamas. While about 600 rockets were fired into Israel during the 22 day campaign, only a few dozen were of the long range BM-21 type, and these did little damage. Iran was also disappointed with the performance of gunmen and combat leaders they had trained. Some of these men were smuggled out to Iran, where they spent months being trained to fight. But smaller numbers of Israeli troops quickly defeated these Iranian trained fighters.
Iran also believes that the 122mm BM-21 rockets they have been providing Hamas are not worth the trouble (smuggling in). These rockets weigh 150 pounds and are nine feet long. They have 45 pound warheads, but not much better accuracy than the 107mm model. However, these larger rockets have a maximum range of 20 kilometers. Again, because they are unguided, they are only effective if fired in salvos, or at large targets (like cities, or large military bases or industrial complexes.) There are longer range (up to about 40 kilometers) versions of these rockets. These are made by a number of countries, and gain their additional range by using smaller warheads.
Most locally made Hamas rockets (Kassams), are based on the older Russian B-12 rocket. This is a factory made, 107mm, 42 pound, 33 inch long, rocket that is very popular with terrorists. This rocket has a range of about six kilometers and three pounds of explosives in its warhead. Normally fired, from a launcher, in salvoes of dozens at a time, when used individually, it is more accurate the closer it is to the target. This 107mm design has been copied by many nations, and is very popular with guerillas and terrorists because of its small size and portability. Hamas has little need for the B-12, because their locally made Kassam rockets match it in range and lack of accuracy. But some B-12s are smuggled in anyway, usually by non-Hamas terror groups that Hamas shelters in Gaza.
Iran is apparently concentrating on smuggling longer range rockets into Gaza, like their Fajr-5. This 10 meter (31 feet) long, 333mm (13 inches) diameter, .9 ton rocket has a range of 75 kilometers. It could reach Tel Aviv, and most of central Israel. But the Fajr-5 is as big as a telephone poll, and is based on a similar Chinese rocket that Iran bought in the 1990s. Fajr-5s can be moved through the smuggling tunnels to Gaza only if broken down into 8-10 sections, and then reassembled on the other end. Getting the pieces into Egypt is not easy, and trying to smuggle them in by sea is very risky. But the Fajr-5 carries a 200 pound warhead, with about a hundred pounds of explosives. Makes a big bang, and is only effective if aimed at a large urban area. That means that the most likely victims will be civilians. Iran is betting that Israel will not retaliate when Israeli forensics experts examine the pieces of the missile after landing in an Israeli city, and identifying it as of Iranian manufacture. Israel did not strike back at Iran when smaller Fajr rockets were fired at Israeli cities in 2006, by Hezbollah in Lebanon. But Israel would certainly go into Gaza if a Fajr ever landed in Tel Aviv.
Iran feels humiliated now, by the country it says, loudly and frequently, should be destroyed. So there apparently is an effort to get Fajr-5s, or similar large rockets, into Gaza. But getting Hamas to fire them is another matter. Hamas is under a lot of pressure from European and Arab supporters, to give up its genocidal plans for Israel and to concentrate on improving the lives of Gazans (many of whom blame Hamas for the war earlier this year). Even Hamas hardliners have to confront the fact that they put in a pitiful performance against Israeli troops back then. Firing a few Fajr-5s into Israel, and then getting blasted by a thousand Israeli smart bombs, missiles and artillery shells, gives one pause. But Iran is supplying Hamas with much of the cash that keeps the organization alive. So Hamas is trying to replace the 2,000 rockets it lost in that war (including 1,400 destroyed by Israeli bombs, shells and troops), will continuing to upgrade the skills of Hamas fighters. Iran is also smuggling in anti-aircraft missiles (like the SA-7/18 types), to be used against the Israeli helicopters that are frequently seen over Gaza. These are easier to get through the tunnels, but the Israelis have equipped their helicopters and low flying fighters with countermeasures to SA-7 type missiles. So the main Iranian goal remains getting rockets that will hit Tel Aviv and other large Israeli urban areas and military facilities.