So once more some notes on Traveller: The Icy Shores. I always had some problems with the idea of piracy in Traveller. It's just strange to pile into a ship cruise over to another ship that is probably as fast as yours and shoot it up to plunder cargo ... leaving a multi-million dollar ship behind or taking it and offing the crew and proving you are a sociopath worth the Navy's bother to hunt down and blow out of the stars. Not to mention in most settings the prey probably has missiles or lasers capable of shooting hell out of your ship.
Quite apart from how hard the pirate is to catch it's just not a cost effective return.
Mind you I do not have a problem with piracy itself. I'd just practice it differently. There are ways to bring the effort and cost down.
Hijacking is one way. Get one of your people onboard the ship, have them hack the computer or otherwise raise merry hell to keep the ship immobile and helpless long enough for you to board. If you manage to get enough people onboard the ship you might even have a boarding action.
Sabotage is another. Stick something onboard the ship to disable it or occupy the crew: emp, incendiary, spambots, combat bots etc. Sticking a virus in a ship's computer falls under sabotage as well. Having a man performing maintenance in the starport will really pay for itself in this and many other piracy campaigns.
Raiding is a different tack entirely. Instead of going after a ship you go after a settlement or station. The target is immobile and can't run making disabling it an order easier. Unfortunately worthwhile targets are usually well defended making it imperative you take the weapons offline first! On the plus side it's probably easier to infiltrate a large number of hijackers and saboteurs on such a targets.
Note the three methods can and will be combined by savvy pirates. Infiltrate hijackers on a station, pop a logic bomb in its computers and grab that choice ship you want that is docked!
I'm inclined to prohibit most non-military ships from carrying conventional weapons like lasers and missiles. This includes the pirates who have to make do with whatever they can scrounge or improvise. Conventional space combat should be rare as it leads to generating a lot of new characters. Making piracy a game of sabotage and subterfuge can lead to more roleplaying opportunities IMO.
I know people will find ways to build or improvise weapons. A lot of the technology in space travel will be inherently dangerous (mining lasers, mass drivers, rocket boosters, nano.) But again tricking out your ship becomes more a matter of skill and roleplaying than plunking down the credits. Also note that you would need software to make attacks hit at long ranges. Which means using subterfuge again, getting close, or pirating software.