Fair warning: This build requires you to have good aiming skills in order to land consistent headshots, if you find that you are missing too much even with all that Stability and Accuracy then use the MDR AR version of Sentry.
Devil & Heel are a great pair of MMRs but it's usefulness can only be fully unlocked with a Sentry set.
You should have enough damage to melt NPCs at any range, if you manage to get both (useful) damage buffs from the exotics ( 30% HS damage, 15% AWD) plus the 100% HS 30% AWD from the Sentry marks you should be able to hit easily for over 1.2 million damage per hit. At the RoF (Rate of Fire) of these weapons and with your ability to handle them should let you mark and melt NPCs pretty fast, faster than any other non-glasscannon DPS build in the game. Remember that you also get 30% Stability buff with a Headshot.
Sentry is king in almost any PvE content and with this build you'll need to learn how to switch between your shield pistol mode to your full DPS MMR mode effectively and you'll become the most versatile player in the game.
The Predatory weapon talent plus medkits should be enough sustain in most situations, if you find that you need more healing because there is no healer in your group and you are being heavily targeted by all NPCs then, most of the time, your teammates are not pulling their weight enough and you are carrying them so act accordingly.
The Reactive Targeting Ballistic Shield is the key to achieve the versatility that this build will give you since you'll be protected against rushing/flanking NPCs, even with the 1.8 shield health nerf you'll have enough (770k HP Mods) to be able to withstand most NPCs long enough to be able to fully mark them (6 marks) and start dropping them to the ground. Remember that you can take cover even with your shield still activated so you can melt down any 6-marked mobs with your MMRs.
You are no tank so keep always an eye on your shield's health and backup and take cover when it's about to break, the Reactive Targeting mod should give you decent mobility in order to take good decisions about your position and to easily avoid any hostile grenade coming at you without rolling away.
Your Second Skill could be almost anything to suit your needs. If nobody has a CC (Crowd Control) skill then go flash sticky. If you feel like you need more healing or to revive your teammates that much often then go with Support Station or Defib. If your team doesn't have any pulse and you need the position awareness of enemies then grab the pulse.
You should be using your Survival Link often, use it when facing large numbers of NPCs or when you need to push against those high damage ones. Activating it will give your shield even more damage resilience and will last quite a lot more during those pushes.
Some good examples on when to use it are:
Since you have Coolheaded in your weapons you'll get it back in the same time that your immunity timer is up so don't be afraid to use it.
If you find that you need to revive your teammates a lot you could change it to Recovery Link but if this is happening then you are probably carrying them, so again, act accordingly.
Working on it...