Particle cannons, unless things have changed, do not have very long ranges because they don't gain a range bonus from weapon size.
For all intents and purposes they do, because one of their tech lines is for range increases (the other being for damage). My Aurora is crashing on startup right now so I can't check, but IIRC it doesn't take long until their nominal range is >1m km.
The Particle Beam 1m km tech is a million research points and is the second to last range tech, so good luck getting that in a normal game. Compared to the fire control range tech at 1m RP, which gives 150,000 km base range. 4x size and 2x that for max range means 1.2m km range for lasers and railguns at that tech level.
A more reasonable level for a normal game, say 30,000 RP, give 320 kkm particle beams and 384 kkm fire controls. Like I said, particle beams consistently lag behind the range of your fire control (and thus large aperture lasers and railguns, which tend to have massive ranges in the millions of km but are limited by your fire control).
Compare this to say, lasers. Lasers get a maximum range tech path, but they also get a range multiplier based on size. So even though the techs for laser range have smaller numbers than the techs for particle beam range, in practice the range of a large laser will be massively higher (though it will be limited by your fire control).
For example, using the same tech level for everything:
30cm Soft X-ray laser: Maximum range 1.44m km
Strength 9 Particle Beam range 320,000: Maximum range .32m km
Beam Fire Control S02 192-6250: Maximum range .384m km