This is my attempt at making a condition-less version of my Handheld Railgun build.
For actual use I would recommend using a Primary Deadhead arcane; I'm not including it here because it's technically a conditional effect.

Comparison between this build and the original (without arcanes on scoped bodyshots, higher value is bolded):

• Base avg damage: 50,798 / 13,556
• After 1 headshot kill: 50,798 / 40,045
• After 2 headshot kills: 50,798 / 56,095
• After 3 headshot kills: 50,798 / 74,726
• After 4 headshot kills: 50,798 / 95,940
• After 5 headshot kills: 50,798 / 119,736

These numbers show that, while an interesting idea, this build isn't particularly great*. The original rivals it in damage after a single headshot kill and exceeds it after another headshot kill. The gap continues to grow after that, with the original eventually reaching a little under 2.6x this build's damage at max stacks. As long as you see an enemy that can be headshot at least once every 6-ish seconds, the original is far better than this build.

*Edit: Actually, this build is great in the hands of one of your Railjack crew members. Crew using your weapons don't receive conditional buffs like [Bladed Rounds] or stacks from Galvanized mods. This makes this build much better than the original in this case. Also, while I'm here, I might as well note that Rivens only apply for crew weapons in Railjack modes. They don't work when you call in a crew member into a non-Railjack mission.

Crew members are also (probably) not affected by anything that can be put into the Exilus slot, so if you're making a mod loadout with this specifically for a crew member to use you could take out the Exilus mod for some more flexibility when modding.