Impact Guns are taking pre-orders for civilian-legal versions of the FN P-90, the gun featured in Stargate Sg:1.
The legal versions will come with a longer barrel, apparently so that the weapon, both in terms of overall length and in terms of barrel length, will be designated a rifle rather than a machine gun*.
Also restricted will be the armour-piercing rounds that were specifically designed for the P-90, but civilians will be able to buy standard 5.7mm ball rounds, easily enough for home defence or target shredding.
They just won't penetrate a Jaffa's armour.
Oh, well, I guess I'll have to settle for an airsoft version until I can buy one...
*It should be noted that, with appropriate documentation and processing by the Bureau of Alcohol, Tobacco and Firearms, the short-barrel version can also be yours.