Hello, RRU!
This is my first ever topic, but by no means am I new here. I just haven't had anything worth making a topic about...until now.
Without further ado, I want to announce that I have solved the long-standing laser bug in Rock Raiders.
I first picked up on this issue while playing Baz's mod. The lasers had a bad tendency to pass through walls and not hit them. Since Axel's mod used the aforementioned mod as a base, the problem carried over. I in turn used Axel's mod as a base and embarked on my own modding adventures. As expected the laser problem persisted, and all attempts to find a solution here came up empty handed.
That's when I happened upon @aidenpons mod, Monster's Revenge. To my complete surprise, the lasers functioned correctly. After reaching out to and talking with aiden today, I tried poking around in the cfg file to see if I could find something. In the WeaponTypes {} section, which is where the lasers are stored, I compared side-by-side the information entered in Baz's/Axel's mod vs aidenpons' mod. What jumped out at me was the stark difference in the WeaponRange values: aiden had the BigLazer at 480, while Baz had it at 10,000. First I lowered the value to 3000 and began seeing the lasers make contact with the walls more often. Finally, I lowered the value down into the range in aiden's mod. The result? Lasers now work correctly!
aidenpons was able to confirm this.
Thanks again to aiden for making his mod; I owe this fix to him.
Update 11/29/2017:
So I finally was able test this more rigorously, using every laser and at every angle you can imagine. I have determined that the lasers will bug out no matter what when you try to hit a wall near the border of a map. Here's why: when facing a wall a few squares from the border, the laser fires through it. Back up, and it hits. The why part is simply that the laser range is outside of the map when you were closer to the wall. When that occurs, for some reason, the lasers start passing through walls instead of hitting them. It's not a big deal as long as you can keep the laser within range of the map (e.g. put more distance between you and the wall).
Ultimately the problem may be hard-coded, but at least we know now what we're dealing with and how to get around it (for the most part).