Jerrythelocke,
I can give all the information that you want with pneumatics, longs, shorts, with Mamba system and without it (these kits allows to shoot with the barrel dry) and also sell you a custom made gun.
I live in Texas and fish with them here in the offshore rigs and with bands too, before I lived in Spain and in Venezuela where we have huge fishes and most of the people use long pneumatics (in the 50”-54” range) and loaded up to 350 psi.
But you are going to a place where will be difficult to find O-rings, shafts with 6 mm threads, slide rings, and so on.
I will recommend you like the rest of the people a band gun with the following characteristics:
Simple, powerful and capable to be fixed with a Swiss Army knife in the middle of nowhere and drunk
There are several in the market Rob Allen, Rabitech, Spetton, Orca Thula, Wong, etc
Just find the one that you feel comfortable with, remember that the best gun it the one that use more comfortable and works for you.
Anyway if you still interested in pneumatics send me a PM and I will be glad to help you.
Cheers
Ivan
ivan@spetton-usa.com
ivan@freediveforlife.com