Ser No Effected Details of Change Effect Confirmed by Tippmann
< 1195 RoF Increase = Clockwise Owners Manual Confirmed
> 1195 RoF Increase = Counter Clockwise Improved RoF sensitivity Owners Manual Confirmed
> 2500 Improved tollerance of hopup hole in upper receiver removing potential for right hand hook of bbs Shapeways / Defcon Nubs may require sanding to fit in later ser no's and some earlier ser no's. Yes
Introduction of additional spacer to recoil assembly Improved RoF stability
< 500 New sear spring introduced to improve sear catching on rear bolt - new sear coloured Blue Reduce likelyhood of sear not engaging Yes
Introduction of new feed nozzle spring
Source : Mark Akehurst (Tippmann Arms Airsoft Owners' Group)