A quick look at an upgraded TM MK46 NGRS AEG done by Eagle6 Airsoft in the UK... "Richard from our tech team talks about and demonstrates a customer's upgraded TM MK46 NGRS AEG build. Please find the full build description below.

FPS Results:

• 321 FPS (Measured On 0.20gr BB)

Scope Of Work:

• Increase power and reliability, and increase the guns ability to lift heavier ammos.  Thus increasing range and accuracy.    

Installed:

• Strip, Prep & Rebuild
• RetroArms Bushings For AA12
• EagleSix M90 Upgrade Spring For MK46
• Firefly Hop Rubber
• EagleSix Custom Flat Nub

Tested On 7.4v 1300mah Lipo Battery

This RIF was put through our '4 point testing' prior to dispatch."