Yep, and federal weapons charges are usually not eligible for parol or early release. If you get convicted, you can expect to do 100% of the time and will never be allowed to possess a firearm or ammunition again.
There is no legal possession of firearms when committing a crime.
You may get out of the drug charges in a plea, but the weapons charge normally is set in stone unless you have one hell of a lawyer.
But you would have to be busted by the Feds, in order for it to be Federal....unless you had enough to get you on Gun Running...or interstate something-- Also, if they plea you out, it will depend on your deal...they can also drop the weapons charges...and often do, if it is apparent that it was a small personal grow, and the guns were not assault rifles and shit..and were locked in a safe--