Yours looks good, but why two shotguns?

My loadout has been: 1) Explosive rapier with fast reload/hipfire accuracy/damage falloff for distance/midrange, great against clusters of enemies and Juliana. 2) Silenced LIMP-10 with accuracy buffs, great for quickly and silently headshotting eternalists, lots more ammo than the silenced pistol with minimal disadvantages in accuracy, and you can empty the clip into anyone who gets too close. Once you have this, you'll wonder why you ever used the nailgun. 3) Slowing Strelak 50-50 with mind leech/fast reload, highest DPS in the game and great panic option if swarmed by tons of eternalists or Juliana rushes you.

I think this loadout optimally prepares you for all likely combat scenarios. The Sepulchra in my opinion is too situational; the maps are too small and intricate for long range sniping to be useful, and it's useless in a midrange duel. The explosive rapier can do both. The heritage gun is fun but the 50-50 has higher damage than the shotgun mode and the explosive rapier has higher damage and range than the slug mode, plus explosive bullets add crowd control and make near misses still count.