Well here you have it, I can safely say I have assembled, constructed, and put together a real SPR-Special Purpose Rifle...
First Purpose- Sniping
590mm Tightbore
Long "Intimidating" Silencer
6x32 RG Scope
Second Purpose- Assault
455mm Tightbore
ICS QD Silencer
4X20 AR Scope(Not Pictured)
Third Purpose-CQB
320mm Inner
ICS QD Silencer w/o extra barrel peice
Rear sight + Aimpoint(to be purchased)
Now I know what your thinking, 3 inner barrels, way to much time speant with disasembly, if it was really special and innovative, you should be able to do this at a game.. Simple answer is, I can. Seperate hopup units all installed on the barrels good to go. My body has been altered to simple disasembly, just pull the front body pin, and slide into 2 complete halves with easy access to the barrel.
Pictures

Disasembly
More pictures later.. Comments welcome.
Renegade)