You may want to try out several sites of the Federal courts system to help you. Here are a few,
www.uscourts.gov and
http://jnet.ao.dcn, each site will then have links that may help. Also, your college library my have access to Westlaw and they can run a search for you or if you know a law student or attorney they may be able to help you with Westlaw. Each have search engines and some will link you directly to the most recent rulings on the 2nd amendment, you just need to have patience on these sights. I work closely with the federal judiciary and with every thing government, it's not always easy.
You'll also notice that in all the oaths for sworn/appointed federal employees and new citizens during their citizenship ceremonys, swear to bear arms for the US. Here's one of the oaths for the citizens oath, I hereby declare, on oath, that I absolutely and entirely renounce and abjure all allegiance and fidelity to any foreign prince, potentate, state, or sovereignty of whom or which I have heretofore been a subject or citizen; that I will support and defend the Constitution and laws of the United States of America against all enemies, foreign and domestic; that I will bear true faith and allegiance to the same; that I will bear arms on behalf of the United States when required by the law; that I will perform noncombatant service in the Armed Forces of the United States when required by the law; that I will perform work of national importance under civilian direction when required by the law; and that I take this obligation freely without any mental reservation or purpose of evasion; so help me God.
It may not be exactly what you're looking for, but our founding fathers thought so much of this right, that just about every oath has the statement to "bear arms" in some form or fashion. It's a little different for the employees, law enforcement related or not, but in our oaths none the less.
Good luck.
