I found M5 antimatter weapon in one of the systems. Is there a M6 version? Does anyone know how to use them?

I don't know about the M6 version, but the antimatter weapon fires just like a regular turret weapon; just be a little ways off from the area of explosion. The distance - a whopping 30000 - doesn't seem to literally 30000 (or, maybe I don't know how to measure the distance in this game). It is extremely expensive to reload, too.

If you search around in various forums, and know a little bit about which users actually have direct contact with Travis Baldree and Eric Schaefer, you CAN find out about the "distances" in Rebel Galaxy. But they have left it deliberately a bit murky.

"sm", the standard measure of distance in Rebel Galaxy, doesn't stand for anything. (Use whatever you want in your own mind, "standard measure", "supra-meters", "stellar macrons", whatever.

During development, mainly for purposes of developing ranges for combat, weapons, and close maneuvering, the developers used "km", meaning, well, kilometers.

This, of course, did NOT work for the larger distances of the game and might have become fodder for endless forum debates even about the weapons and combat. They didn't want to get into a more complicated and essentially pointless system of measurements that attempted to really correlate to the real world. So shortly before release they changed every reference to "km" in the game to "sm", and left it ambiguous. Which seems to work just fine.

Interesting side note: In the entire scale of metric measurements, there is no term that can be reasonably abbreviated as "sm". I don't know if that was a deliberate bit of research and choice by Travis and Eric, but I choose to believe in their cleverness and assume that it was.

Vanqishers forever!
dreamrider

Obviously it means Space Meters *obvious shrugging gesture*