WistfulD

Okay, here is a primer (and please jump in to correct me, fellow board members). Let us limit our scope to simple, killing weapons that have one basic function, and thus are not built as multi-powers. Since you didn't provide a book and page reference for your laser rifle, I can't comment on it. Let's build two weapons, a combat knife and a .22-.270 deer-hunting rifle, and then we'll add a scope to the rifle.
 
Knife - A knife is HKA 1/2D6 for 10 base points.
Advantages:The knife is armor piercing (+1/4), and doesn't cost more Endurance than the STR used to swing it (reduced endurance: 0 END; + 1/2). That makes it 10*(1.00+0.25+0.50) = 17 Active Points (remember 17.5 rounds to 17).
Limitations: The Knife is an obvious, accessible focus (-1). We could decide that it is inobvious, as a combat knife could mean a switchblade or other easily concealable tactical folder, but we decide that it's more of a Rambo-style knife. Now it's a "Real Weapon," but it is a modern knife in modern times, so maintaining it isn't likely a real burden. We'll say that we're building it for a heroic, instead of superheroic game, so taking the real weapon limitation is assumed (and thus -0), so we won't worry about it. Likewise, restrainable is inherent to a focus you take out and weild with your arms (-0). The weapon ends up being 17/(1.00+1.00) = 8 Real points.
 
Rifle - how much an individual gun does is really dependent upon your campaign. To make life easy, let's make our rifle do RKA 2D6 for 30 base points.
Advantages: There easily could be no advantages to add to the active cost, but let's think about the range, since you brought that up. The basic range of the weapon is in fact, as you suggested, the same as the power. That would be 30 (base points) x 10m = 300m. How far a bullet travels if you ask it in a high school physics question is not the distance you can successfully hurt something with it. Since we aren't converting the thing into a sniper rifle, let's say that over half a kilometer is unlikely, and give it one level of long range (+1/4) and a maximum range of 300 x 2 = 600m. Looking over other potential advantages (armor piercing for armor piercing bullets of course, indirect for mortar rounds, no range penalty for guided missiles maybe), nothing else looks too important. Thus our rifle is going to be 30 x (1.00 + 1.25) = 37 active points.
Endurance/Charges: Note that we didn't pick up reduced endurance (0 END; + 1/2) for this one. Therefore, we have to explain how it pays for it's effects. Since it doesn't have an endurance reserve (although a self-recharging laser rifle or something might do that), and the weilder can't pay the END cost (as a magic wand might allow), it is going to have to use charges (bullets). These will be simple cartridge based clips. We'll say it is a 4-cartridge clip, and that no special rules about clips or reloading time or anything apply. This will be a -1 limitation that we'll add in with the limitations. If it was a 30-round tommie-gun drum clip, it'd instead be an advantage.
Limitations: The rifle is an Obvious, accessible focus (-1), and we already covered the charges limitation (-1). A rifle needs maintenance or else it will start to jam, so it qualifies for the Real Weapon (-1/4) limitation, but we've already stipulated in this campaign that maintenance requirements are an assumed part of equipment, so (-0). The rifle is two handed, for a (-1/4). Trying to shoot it one handed will subject you to some significant penalties. Same with firing it if you are a 80-lb weakling, so take STR minimum (-1/4). Finally, the gun qualifies for the Beam (-1/4) limitation. You can shoot a person, or possibly shoot a lock off a door, but if you actually have to cut your way through a wall or something, your little tiny bullet holes are going to do bupkiss. Thus your rifle ends up as a 37/(1.00+1.00+1.00+0.25+0.25+0.25) = 13 Real Points.
 
Now some weapons have innate bonuses to OCV or Rmod, which we would have to add, but let's do that with the scope.
 
Scope: this adds powers to the rifle. It could include basic OCV, range penalty remission, or even darkness penalty remission. For simplicity's sake, we'll limit it to range. Let's say that we want to be reasonably able to hit something at 100m, a +8 rMod. That's just 8 2-pt. Penalty Skill Levels taken with obvious accessible...whatwhatwait? Oh no! Penalty skill levels for a single weapon cost 2-pts apiece. You cannot apply limitations to them. Alright, we'll find another way around this. Okay, since we aren't using a power framework, active points are not our primary concern, real points are, so let's use basic OCV (5 pts. apiece). Eight levels of that are (8 x 5) 40 active points. To that we can add Limitation (only to counter range-based penalties; - 1/2), limitation (bonus only applies when set or braced; - 1/2), along with OAF (-1), and real weapon (-0 in this case). Thus, the scope costs 40/(1.00+1.00+0.50+0.50)=13 extra points.
Another method is to use 3-pt. PSLs, even thought the scope presumably is designed for one type of weapon (rifles) and thus qualifies for 2-pt PSLs (but 3 pt. skills can apply limitations). Check with your GM. That makes the active costs (8*3) 24 points, but of course you can't apply the (only to counter range-based penalties; - 1/2) limitation. Thus the total real cost is 24/2.5= 10 points.
 
Taking a guess at your laser rifle, It could be RKA 5D6 for 75 Active Points, but it could be 4D6 with a +1/4 advantage (perhaps the GM is applying Inobvious:does not leave bullet casings at scene to the rifle, perhaps it is armor piercing, or a level of extra range). To get to exactly 24 real points is a challenge (2 total points of limitation would be 25, 2.25 would be 23), but adding a bit of OCV, Rmod, and who knows what else won't make it ridiculous.
 
Yes, weapons are a lot cheaper than powers. They can be taken away, shot, and usually come with charges instead of being power by your END (and rarely have > 16 charges). 

Not really. In a heroic game, We generally figure that a character gets knocked down when they are tripped (or at least the equivalent effect), and when they are put down below 0 stun. We rule that being lightly below 0 stun (such that they'll recover in a turn) means that they are extra staggered, and will fall down and drop what's in their hands, but still be concious.