ok, welcome to the forum sky, can i humbly quantify something...reading your post you were denied from purchasing a
rifle from a FFL i presume during their routine FBI NICS check?
if that is correct, i know your denial didn't have a bloody thing to do with past DUIs! therefore, is there something else in your past you have not been forthcoming about?
either way you need to discern the true reason you were denied.
here is the FBI's NICS appeal brochure link:
http://www.fbi.gov/about-us/cjis/nics/appeals/nics_appeals_brochure_eng which has at the bottom a listing of rationals for denial and as you see DUI doesn't seem to be there, so you might begin to look at and implement the steps to discern the specifics of your denial instead of bemoaning a woe is me mantra i was denied due to DUI, and running off trying to fixing that, you could ask FBI NICS what the real reason was and then begin gathering information to appeal it>
again welcome to the forum glad we could assist with the purchase of your LG.
btw, i am not an attorney either, therefore the advice was provided w/o cost!
ipse