as meny fallout 3 fans know the Gauss rifle was a very cool weapon that you got for compleating operation Anchorage. it was a scoped energy weapon that made the game a lot of fun i for one would like to see it rettern

There was also another type of Gauss Rifle and Pistol in Fallout 2 which fired metal slugs, which in my own opinion at least put the one from Operation Anchorage in Fallout 3 to shame.

Gauss weapons are ballistic weapons, they shoot tiny diameter hypersonic flechettes. They just don't use thermal expansion as driving force, instead magnetic accelerator is used give initial speed for projectile. Gauss weapons aka rail guns are common is scifi, in real life those have been developed, but portable size application of technology isn't coming soon. US Navy has plans to introduce gauss cannon into service within decade if everything goes as planned, system will have weight in hundreds of tons and will need to accompanied by nuclear reactor or gas turbine to generate enough power to operate.

In Fallout 3 it ended up being energy weapon due to game design glitch, there wasn't good long range weapon in energy weapons as laser rifle of previous games had been replaced with something like assault rifle.

As fun as the Gauss Rifle was, leave it for FO3. I'm sure we'll get something just as equally cool in NV.

The one in New Vegas fired metal slugs too, that's exactly what a Gauss rifle is, it uses electromagnetic coils to accellerate metal slugs to high speeds and fire them at enemies. But Bethesda put it under energy weapons anyway, probably because they wanted to add an energy weapon to fulfill its niche, since there are not many options for an energy weapon user in Fallout 3.

If the Gauss rifle does appear in New Vegas, though, it should not be an energy weapon, it should be a small gun or maybe a big gun, I'm not sure if it's large enough to count as a big gun so small guns is probably the best place for it, if Obsidian wants more variety in energy weapons, they should build off what the skill already covers, not make things that shouldn't actually qualify into energy weapons.

There is a http://www.gamesas.com/index.php?/topic/1088918-weapons/, no need for individual topics on each type of weapon you want in the new game.