I am considering acquiring a receiver or two for future build projects (although I won't be doing the work myself). Of the two AK74 receivers I see available, there is the NDS-2 & AUSA 5.45 x 39. Is there an advantage or negative to either? Also, wanted to know about the gas piston tubes. Is there any appreciable difference (other than the gas escape holes) on a AKM tube -vs- one for a AK74? Lastly, want to get some 922r 5.45 x 39 followers. I have some Arsenal 922r floor plates & followers for 7.62 x 39 (and understand the floor plates will work on some 5.45 x 39 mags like Bulgarian). Have seen reference to "Grasshopper" brand followers but have yet to find the source for them. Thanks!