Systema PTW M4 CQB/CQC. All the accuracy and range of the longer barreled models, but much shorter and wield-able. Throw a black cylinder in 'er and you're good for indoors.
A good budget option is the VFC XCR.
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