The problem with this is that in the 75 years since WW2 artillery has changed completely. Back then it was a case of have dozens of then fire at a target repeatedly for 5 minutes and probability says you have a good chance of hitting near it. Modern artillery pieces are a case of dial the GPS coordinates of your target into the computer, let it account for angles and wind, hit the fire button and your shell should land within a couple of meters of your target point.
Russia didn't care about the resources of Syria, they just didn't want extremists to take over a country that's closer to Russia than Edinburgh is to London, and unlike the west had no qualms about propping up Assad's dictatorship to achieve it.