What SMF TSO said... and a second ^ for SKB cases....although I must say I just use my Samsonite hard shell suitcase.. which has the added advantage of not looking like a gun case!
I've travelled to/around the USA numerous times with guns (generally 2 pistols + a rifle and shotgun) and never had any dramas with the TSA folks...
You MAY have some check in staff who are unsure/unhappy about it.. but that happens less often these days (compared to say 1997 when I started travellling for competitions).. seems there is more training provided these days????
I just ensure I get there EARLY. Check in staff that are not busy/harried are much better to deal with when you have something "unusual" like "restricted goods"...
Have a good trip!