Can you go to the SFQC, pass for the training, tab, and beret, and then go back to your unit?

No. The Q course is not Ranger school. When a service member graduates from the Q-course he is re-classed to what ever MOS he passed. Unless your unit has MTOE slots for a 18 series then maybe, but not likely. If you were able to pass and earn a tab, why would you want to go back to a regular Army unit. If you are asking questions like this, you don't have a chance.

I am not an SF soldier but have had a few in my unit that left on selection. Once the training was done their MOS was changed and they were reassigned to the SPECOPS Command for reassignment not returned to the unit they left prior to training. This may be different for USANG/USAR soldiers or Officer branches but my enlisted soldiers were GONE.

Not possible,

Once you are selected (can feed into SFAS from any MOS) you would then be in the pipeline (AD) for an assignment to an SF Group. If you were in the ARNG, you would also be assigned to 19th or 20th Grp and would go back to those units and serve. I have seen ARNG NVOs and Officers get additional MOSs/Branches and serve in those branches after as they progress in rank and positions get harder to come by; but that is more the exception than the rule. So is it possible, in that case yes; but unlikely-at least for a time after you complete the Q course.

Why would you be asking this question? If you just want a tab go to sapper or ranger school; if you want a beret stick with SF and live the legend. If your confused; go Infantry, excel at that, gain experi nice and knowledge and the go the SF route so you can succeed and be vested in the process and future.

De Opresso Liber

DB