Although M-16 and M-4 assault rifles are much more effective when used with up-to-date optics (scopes, night vision, red dot and so on), not all the troops in Iraq and Afghanistan have these accessories. Even with the Rapid Fielding Initiative (RFI), which provides additional money to buy needed equipment from manufacturers and ship it straight to the troops, many troops are without these more effective tools. Sometimes theres a reason for some troops not getting the optics. Support units wont have much opportunity to use these expensive items, except that many support troops are running combat missions several times a weeks as they man weapons on vehicles protecting supply convoys in Iraq. In other cases, artillery or tank units being used as infantry just get overlooked when it comes to handing out the RFI goodies. So many of these troops are just buying the options with their own money. The cost can be from about $200 for a simple scope, to about $1,100 for a night vision scope. The troops will also buy slings (that make the weapon easier to carry, and quickly use), back up iron sights, bipods (for automatic weapons), magazines (that are more reliable than the ones issues). The brass have become aware of this, and are trying to get the rifle accessories to more people that need them. The troops who get this stuff via RFI, or the regular supply system, far outnumber those who have to buy it themselves, so this has not become a major issue. Its also understood that, when some new item appears on the commercial market (mainly for hunters and police), the troops that buy and use these goodies will report their experiences to other troops. These reports quickly get to the army weapons and equipment bureaucracy, and are usually quickly acted on. The alternative, as the bureaucrats have learned, is for the troop reports to get to the media and members of Congress. This can have an adverse effect on a bureaucrats career. Not a perfect system, but it works.