autogun lines

hey so I thought of upgrading my auto gun which i have since 2012 :P
Which would be best, pepperbox, blitz, plague or dark chain gun line?
I have 2 shadow guns (sentenza and bio), 2 piercing (riftlokcer and callahan) and one elemental (nog blaster). I got no 5* normal gun yet.
I don't do vana much, neither do I do jelly king a lot.
I could need some help deciding on a line. Thanks for coming help!

I generally agree with Holy-Nightmare here. But I would go for this loadout specifically:
* Callahan
* Nog Blaster (Nova Driver)
* Dark Chaingun
(Or just carry two of them at a time.) Then you have all three non-normal damage types, and you have all three styles of charge-oriented gun. So get armor that enhances your handgun CTR, such as Seerus or Chaos (or Padded). Then you can just destroy everything.

thx for the tips and ideas :) I think I'll go for the dark chain gun line, Bobb's idea sounds great :D (btw my gunner set is seerus + sentinel, great for charges :D)

A dark chain gun would solve JK or rooms full of gremlins - no question. I don't have one yet (I use an Umbra for my shadow weapon), but it's on my shopping list. I'd suggest that be your first choice.
Blitz is also great. Blitz + [pick one: DA, Combustor] is almost the standard hybrid loadout for Vana. I've also done Vana as a gunner using Blitz + Storm. (Nog would have worked just as well. Mostly I used Blitz.) But you already have a perfectly good Callahan for your piercing gun, you don't do Vana much, and you seem to want a pure gunner build.
I have a pepperbox as my normal weapon, but I find I don't use it much. The fire and knockback aren't quite enough to make up for the lack of damage.
I don't have a Plague needle yet either, and it's not very high on the shopping list. Its main purpose seems to be to counter menders. I suppose that tactic works, but fiends or wolvers (the two main targets of a piercing gun) seldom appear alongside menders. I'd suggest skipping it and just killing any menders first with your Chaingun, Blitz, or Callahan.

From my point of view, all of the autogun line guns are boss killers.
The Pepperbox line can change the RT phase in one charge attack. It can also kill JK very fast. It may not be so good at vana, but it is pretty good.
The Grim line of autogun i.e. Grim repeater, is very usefull for JK. It is the best gun to use if you farm JK alot. It is also good for a mob of gremlins (Deconstruction Zone, etc.)
The Blitz line of autogun i.e. the Needle line, is what I would call "the best gun for defeating Vanaduke". It's like the anit-vana gun. It also one charge kills trojans.
The Plague like of autogun has a bit lower piercing offence than Blitz Needle, but it also gives you a posion status, which stops enemies from healing, and gives you better damage.
You should get the pepperbox line. It deals with normal damage, and is also good for ALL bosses. It's also good at DPS. If you would have mentioned about RT it would have been easier, as the Pepperbox line is the best autogun line gun for RT.

I always use it for Decon zones, the knockback sends gremlins away, and sets them ablaze. Not to mention the regular attack now has better range and deals fire with normal volleys, it's a very well-rounded gun!

Grim Repeater also absolutely destroys Operation: Crimson Hammer, if that's of any interest to you.
All are pretty good, autoguns lines always have great charge attack DPS.
I would suggest the Dark Chaingun since your shadow guns are rather weak compared to your others. Next I would suggest the Pepperbox line just because it is universally useful. Both of these guns have knockback and flinch on the charge making them rather safe
The Plague and Blitz lines are more powerful since they don't push enemies away but if the enemy doesn't flinch they are still close enough to hit you.
My personal favorite answer is to get them all, I currently have 1 of each line and have 1/2 of them at 5 star already, they all have their uses and have different playstyles.