Free: Contests & Raffles.
For tickets purchased on or after February 1, 2010:$25 for the first checked piece. Exceptions may apply.$35 for the second checked piece. Exceptions may apply.$100 per piece for the 3rd, 4th and 5th checked bags$200 per piece for the 6th checked bag and any additional pieces
Checked baggage which is larger than 62 in/157 cm will be charged at the rate of $150 per piece.
I would do what Jackelope suggested, fly down, and then mail all the guns to yourself. This way you don't have to pay a transfer fee to an FFL holder. That will save you about $150 right there. The cost of mailing each gun shouldn't be too high either, maybe $15 or $20 each.