I am a bit confused by your answer when you say you entered a guilty plea AND entered into the ARD program. It is a critical distinction because if you entered a guilty plea to any drug charge, you will never be eligible for a concealed carry permit in Pennsylvania. However, if you entered into ARD and successfully completed it, it should not have resulted in an actual conviction and should not be a bar to obtaining a permit. Answer the question on the application appropriately as to whether or not you were "convicted." Good luck.
Bradley Law Firm, LLC
Also, even if you went through the ARD program, you may have to file a motion to have the record expunged, This is because the record of your arrest (not a conviction record if you went ARD) will still be in the criminal background data base, unless you get it expunged.