imported post
Point of Note:
The MetalStorm weapons are NOT railguns.
They are still, essentially, traditional firearms, launching the projectile with burning propellant. The primary differences between Metalstorm firearms and "traditional" firearms are this:
1) the propellant charge is ignited electronically, not through a mechanically-initiated chemical reaction (they use no primers), and
2) the barrel IS the magazine, so there is no "feeding mechanism" per se, which tremendously increases speed of fire and reliability.
The major drawback to the MetalStorm technology is if a propellant charge fails for some reason to ignite and then the next one behind it DOES fire. The resulting increase in pressure could cause catastrophic failure of the barrel, and could, in theory, cause multiple simultaneous propellant ingnitions. Personally, I don't want to be holding 20 rounds in my hand when they all go off because of a "failure to fire"...
Rail guns use NO propellant to launch their projectiles. They use electromagnetic pulses cycled through a series of coils.
The DOD has been working on rail gun-based artillery for decades. Some of the experimental units ARE capable of launching impressively large payloads with tremendous velocity--far exceeding that of "traditional" artillery. The part of rail gun technology that is holding these weapons back in terms of field deployment is that they require unfathomable amounts of electricity to operate, and tend to have a relatively low cyclical rate of fire compared to traditional guns, and have an unacceptable MTBF service life, compared to traditional guns.
Rail guns might someday become practical, but for the foreseeable future, they are inefficient, unreliable, and impractically bulky.
Useable hand-held railgun weapons of ANY practical type are several decades away, and even then, they will still have a much lower rate of fire and terminal velocity of their projectiles than traditional firearms of similar size, weight, and cost.
Same goes for "energy weapons" like lasers, masers, or sonic weapons.
There are some "practical" uses for rail guns. They might be VERY effective launch platforms for unmanned space vehicles like satellites, or cargo ships. But they can not be used to launch humans into space, because the acceleration needed to lift a manned vehicle out of the gravity well would create, as they say in the medical field, "a condition incompatible with life", meaning, you'd be killed by the G-force of the acceleration...