Hmmm this 51T is not what I thought...

[No2sc2]

It's awesome solid!!! I had to have the wrench to tighten it down!

 

[Twitch2120]

Saker? The 51t mount is fixed by machining an angle on the collar. You could also machine the can but I think that requires a ffl of sorts. Perhaps sico made their adaptor with better fit. I will never own an aac 51t. I prefer full threads like the TBAC or sas or ttf. Never got the idea of qd. One mag down the tube and its not very qd anymore.