Mandalore is a bit sub-par compared to the other ranged characters in the game. You can compensate for it to an extent - a fully-upgraded Repeating Blaster Rifle or Charric does nice damage. His big penalty is the inability to change armor - even with upgrades, it doesn't hold a candle to some of the other armor options.
For sheer damage output at range, the best character in the game is a Jedi with two pistols using Master Speed. When each pistol is doing an average of 30 points of damage, firing 5 times per round (with Rapid Shot), that's about 150 per round - significantly more than Mandalore can dish out.
Honorable mention goes to HK-47, for his ability to kill 'boss' targets. Max out the sniper shot feat tree, give him a rifle with a high threat range, and have him shoot at high hit point targets. His assassination protocols do a great job of whittling down tough targets fast.
One other point to make - while Master Speed characters dish out the most damage, sometimes its better to put a character in armor for staying power. The Electromesh armor in particular, combined with the appropriate upgrades, can make a character nearly immune to Energy damage. Currently, I have Anton in this armor, wielding two pistols with Rapid Shot. His damage output dropped by 40% without Master Speed (3 shots instead of 5) - but I easily doubled his staying power. And I made sure to give him Force Redirection, making him even more resilient versus blaster fire.