This is specifically for the RPG-42 and not the PMCL - the PMCL can be locked onto a target, so precision aiming isn't necessary if it's used correctly - it's a much easier weapon to use. The RPG-42, on the other hand, has no target-locking, and you must use the scope to compensate for distance.
Anyway, let's get started.
![Image](http://i.imgur.com/nogJ03k.jpg)
Enemy armour ahead! It's a Tigris, and it's facing away from us. With some luck a well-placed RPG shot to its rear could potentially take it out. We only get one chance to catch it off guard though, so we better make this shot a good one.
The first thing to note is the arc of the RPG-42 is completely different to the RPG-7 of our A2 days. The RPG-7's rocket kicks in a few moments after launching, giving it a down-then-up arc of movement that is very forgiving - just aim a little above a distant target to be relatively confident of a hit. The RPG-42's rocket fires the moment you pull the trigger, giving the RPG a parabolic arc more like a bullet. This is why RPG-42 shots seems to drop to the floor after 50 metres - they're affected by range much more severely.
The lines and numbers on the scope are there to indicate range, but it's easy to assume, with this being the future and all, that those numbers are there to indicate kilometres. Not true! They represent hundreds of metres. (Click image for full-size)
![Image](http://i.imgur.com/BwSlh4Zl.jpg)
We need to estimate range to use these sights at all - use your map to do this (and get a second opinion from your FTL!) This Tigris is almost exactly 500 metres away, so we need to use the very bottom crosshair to aim. We should look to aim (roughly) around the area where the turret and hull join - this should give us more of a margin of error if the vehicle is a little closer/further away. Our shot should look something like this:
![Image](http://i.imgur.com/7E4k0Iz.jpg)
Once you're lined up and happy with your shot, get the go-ahead from your FTL and pull the trigger. I tend to keep looking down the scope until the RPG has exploded, so I can confirm a hit/miss.
![Image](http://i.imgur.com/aBEzxLM.jpg)
Kablamo! Down in one, just what we wanted. Now go spread this explosive justice across Altis, comrade!