The G26 has the first gen TM GBB adjustable hop, while the basic is the same as the later one the dimension is slightly different, as a result the newer barrel does not fit the G26(FYI all TM TBB for GBB is interchangable otherwise). I think I tried to look for PDI for my G26 but I think they don't make them anymore...not 100% on that though. Try looking through
www.x-fire.org which is PDI's own site...