I stoped Fat boys last week about doing a 9 mm upper and they said the adapters are being droped for a new standard of dicated lowers like Quater circle 10 type Glock lowers , that the standard should be coming out at SHOT SHOW . Does anyone have any more info about this ? Will you need an need a dicated upper like QC10 or PSA locks you into or will be able to use any 9mm barreled upper you want ?