Alumyx posted last month a "lightweight" Silverback SRS-A1 airsoft sniper rifle. He also listed the parts he used in this custom work some parts use Carbon Fibre and the lightened parts and achieved a total weight  1.725Kg naked/2.365 kg with scope & magazine. If interested here is the list:

• Primary Arms, LLC, LLC 1-6X24 scope
• Aero Precision ultra light scope mount
• Carbon handguard
• Carbon / 3D printed outer barrel with Madbul AL-7075 inner barrel.
• Titanium screws & nuts
• Lightened bolt head & cylinder
• Lightened piston
• Nylon spring guide
• Lightened buttplate
• Polymer magazine
• Original receiver & stock panels