In 3E, the effect you are looking for is (as in 2E and Scrollmaster's answer) Variable.
Variable: Action: Standard, Range: Personal, Duration: Sustained. 7points/rank.
There is a -1point/rank flaw called 'Slow' which means your power can't be reconfigured during an action scene, only between scenes. It states that the GM will determine the time, but it should be short enough to happen within a game session but long enough to not happen in combat (it also suggests you can spend a Hero Point to reconfigure in a desperate situation).
You might also want to apply the -1point/rank flaw 'Uncontrolled' to the power, meaning that your character doesn't control the allocation of these points. This would mean the GM would decide how they are spent.
So if you, the player, spend the points once (or possibly twice) per story, it's a 6 point/rank power that gives you 5 points/rank to spend during 'downtime' on a new Device/Power/etc.
If the GM spends the points on your behalf and Q hands you a brand new Austin Martin with a bundle of doohickeys that you have no say over, it's 5 points/rank and gives you 5 points/rank of powers. Just be prepared for it to sometimes be a flying car when you're going to end up being teleported to Atlantis (and be ready to spend a Hero Point and some down time to reconfigure it to a submersible car).
As with any power which can be reconfigured during a session, it may be good to have a basic 'set' of things it can do prepared beforehand (for instance, a set of vehicles with their base cost, and how many points they have left over for customizations) so that it doesn't slow down gameplay too much.
This would strike me as a modification to the 'Limited Use' complication. It all depends on how frequently you have to do it and how long it takes in combat.
Is reloading a free action? That's not a 'Limited Use', it's a description. If you can run out of reloads, that's the 'limited' part of limited use, and I don't know how you'd reload your spare clips. Perhaps you could use a Hero Point to change the scene: "I'd like to spend a Hero Point. When Gobsmacker hit my teammate Glory into that pile of crates, maybe one of the ones that smashed open had a bunch of magazines?"
Is reloading a move-equivalent action? If you can reload and shoot in the same turn, it's not such a huge limitation. Maybe you can weaken the cost reduction of the flaw to -1point/2 ranks?
Is reloading a standard action or a full-round action? At this point, it starts being a somewhat severe impact to the character. I'd say you handle this by saying, "You can reload X times with standard actions." Maybe spend 1 power point per reload, treating them like a power feat.
Does reloading take multiple rounds? If it takes this long, keeping your character out of combat for the duration, I'd argue in favor of it being a bigger issue than simply a power that stops after a few shots. I'd be in favor of it being -3 points/2 ranks (round down) instead of -1 point/rank.
Best Answer
(Assuming 2nd edition) Simply use the two powers one after the other using a Move action and a Standard action. Dash, strike. Simple as that.
Your Dashing power should be either Speed 2 (if you only want to dash on walkable distance) or Teleport 2 (with flaws to limit destination to perception) if you want to be able to dash an enemy even if he's flying or above the ground.
Your attack power will be strike on your device. If you have any strength, take only 1 rank and add the power feat Mighty (so it adds your strength to the Damage bonus).