Not really. They're not as common as say a V2, but they can be ordered. I've carried an airsoft vulcan cannon (mini gun), they are extremely heavy, and very difficult to shoot. Homemade won't suit you, and is hard to pass off for use. A mini gun system uses an electric system to rotate and time the barrels, and a gas one to propel the BB. The weapon assembly weighs in around 50 pounds, that's not including the backpack you may want to run for extra battery and gas, as well as BB feeding; so your gun can shoot for more than 5 minutes before reloading everything. They are very cool, but mostly useless and you wouldn't want to carry one for more than a quick scrim, even if you're incredibly fit and built. On top of that, they aren't very accurate.
At least with an M249, M60, RPK, etc, you can upgrade them to take the punishment, be more accurate and take weapon sights, etc. also, whichever gun you do use you'll want to be able to shoot it, and dump a ton of money into completely upgrading, tuning, and keeping it perfect. 99 out of 100 LMGs on the field do not out range, have better accuracy, or have as good of a rate of fire as your average assault platform. If your gun isn't all that it can be, then your average M4 will keep your head down, and move in on you, quickly killing you before you are even a threat. After an hour or two when your tired of carrying the thing around, you still are only useful if you can bust your ass to the front line and provide support fire before the battle is done.
As for build, I'd take Thunder Cactus's advice. He's had one of the few I've seen that was worth its salt.
ďREALITY IS LIKE A STONE. TO MANY ITíS HARD AND COLD, THEY CANíT HUG IT OR EAT IT, IT ONLY FRUSTERATES THEM AND DOESNíT DO THEM MUCH GOOD. TO OTHERS ITíS STRONG AND DEPENDABLE, YOU CAN BUILD WITH IT, BUILD UPON IT, OR WORK WITH IT, ALSO USE IT TO SMASH PEOPLE IN THE FACE.Ē
Last edited by Ricochet; March 22nd, 2013 at 10:29..