It is known that Syrian rebels have had to rely on jerry-rigged weapons, and it appears some fighters have turned to technology to upgrade their gear.

Mohamed Abdullah of Reuters took this fascinating picture of Free Syrian Army rebels using an iPad to guide mortar fire outside of Damascus. A member of the 'Ansar Dimachk' Brigade, part of the 'Asood Allah' Brigade which operates under the Free Syrian Army, uses an iPad during preparations to fire a homemade mortar at one of the battlefronts in Jobar, Damascus September 15, 2013. REUTERS/ Mohamed Abdullah

Business Insider reporter Paul Szoldra held almost every billet in the 81mm Mortar Platoon and instructed new mortarmen when he served in the U.S. Marine Corps from 2002 to 2010.

These rebels, according to Szoldra, appear to be using an app to level the tube because they don't have sights on the mortars to help level it out and aim at a target.

Here's Paul's analysis of the operation:

The baseplate is way too sunk in (which means they've been firing from that position for at least a while ... every round it goes lower.) You can see the bipod in front how far forward it is.

The other thing is the elevation of the tube. It's almost straight up. Either they are trying to kill themselves and fire a round that will land right back on top of them, or where they are shooting is extremely close to them.

Paul added that even with the iPad, the lack of sights means it looks like "they are simply dropping a round and praying."