Well my axton has decent gear so i dont know where you are in that aspect but i can tell you what I have been doing and how its been working for me.
If you have a slag plasma caster you can go down the survival tree and get gemini (2 turrets) I went 5 points in healthy, prep, quick charge, picked up phalanx and mag lock, maxed resourceful, and grit and gemini.
Then i went over to guerilla and got ready, willing (i have a bee, you may not), scorched earth and onslaught. And while I level I put more points into sentry but you could easily just pick up sentry over ready.
If you dont have a good slag weapon go down guerrilla (skip grenadier and crisis imo) and get double up then you should be ok. Slag is so very important in UVHM its crazy i usually use my slag plasma caster and slag CC and let my 2 turrets kill everything. Also if you use my top build get a cooldown relic they are super helpful as well.
This is what I've personally gone with (obviously with the Legendary COM). I have an explosive weapons setup, and my level 50 DPUH is actually doing pretty good so far against 55-56 enemies. The slag turret is really handy especially if you don't have a good slag weapon like the Slagga (fortunately, I do). I have a 30% explosive relic as well and I use a Quasar grenade to cluster everything together for slagging and getting the most out of my DPUH. --- http://img356.imageshack.us/img356/8325/scrunchface2copyfx0.png http://www.xboxlc.com/cards/default/alle5.jpg