Magazines, AR lower, magazines, pistol (Glock 22 RTF maybe...lots of .40 Glocks in OIF right now), ammo, magazines, good .22 pistol (You are going to be the next grand master in the AMTU, right?
) and more magazines. This really applies if you are going active duty, reserves/NG this is not much of a concern: You are going to have to probably register and store your stuff if you on a CONUS duty station (and forget about taking you toys over seas on duty posts). Once you are done with all of your initial training, and you decide to build your own armory, rent a small secure storage locker off base and store your own gear there and invest in a premium lock. I do not feel that the provost marshal and your unit/HQ has any business knowing and controlling access to your own gear. Discreet is the key word, no one else, including buddies should know. Army brass went apeshit over this stuff about 12 years ago when a soldier from the 101st went batshit and started plinking at a PT formation with his AR-15 SP1.
Did I mention you should buy magazines?
Buy good stuff, even if you have to save for it. Don't buy gun crap on impulse.
Oh...and get a vasectomy. NOW!!! It can be reversed later on, if you decide to settle down. Have fun with all of the soldier groupies, without fear of one latching her hooks into you for the next 18 years. IT HAPPENS TO SOLDIERS A WHOLE DAMN LOT! And, you will never see it coming, and I am not talking about some nice mamasan or German girl either. American girls out in the middle of BFE too. A major installation will have a pool of available women with high odometer readings. Young, inexperienced, naive soldiers are sucked into this trap everyday. I have seen it happen to friends, subordinates, officers and enlisted. You will be off your feet for 24-48 hours-BFD. Beer and frozen bags of corn will be your friend. Now is the time to concentrate on yourself and be a little selfish... as in-have fun without worries. Except for Korean Accelerated Black Chlamydia Type III-That can be fixed with a wire coat hanger and a rubber mallet and morphine. So invest in some protective covers for your primary weapon too, in addition to getting "clipped".
Don't forget to buy magazines.
Remember this too, it should have been annexed on to the Ranger Creed: If it is worth shooting, shoot it twice. Oh...it almost slipped my mind...buy magazines!