I don't know about that, as in Finland you (a civilian) can buy anything from small caliber pistols and rifles to rpgs, large caliber cannons and howitzers if you have reasonable reason to own such weapon (like filming war movie, weapon collecting voluntary reserve schooling in case of big guns). There are 1.6 million legal owned fire arms in Finland (about 30% of adult population owns a firearm). Between 2003-2011, 17% (185) of all homicides (1091), were committed with firearm (41% of the cases knife or some other edged weapon was used, in 23% of cases no weapon of any sort was used), from which half are legally bought and owned. Big sunk of illegally owned firearms were originally legally bought but have changed hands without doing proper paper work, but also lot of firearms used in homicides have been either stolen or borrowed from their legal owners. In robberies using of firearm is less frequent phenomenon than in homicides, as firearm is used only in 6.3% of robberies.
Meaning that it is difficult to say if gun regulations prevent law binding citizens from owning a firearm and how much said regulations effect on crime rates.
Wonder what kind of reasons they get for someone wanting an RPG.