To hell with versatility. Forma forma forma forma forma.

Dumps big damage on a single target, leaving them crying in their bed wondering what they did to deserve such sodomy. [Pyrana] doesn't care, it will fill them with LOTS OF NUMBERS and bail.

I like the [Pyrana]. Hell, my regular [Pyrana] was forma'd 5 times. So is [Pyrana Prime] worth 6 forma?

Yes.

Now, there is a way to boost raw damage even more (without a riven) via two ways. Heat and slash (putting on [Maim]) or [Magnum Force]. Here is my reasoning for you not doing that:

Heat and Slash: Yeah, slash is great but it won't melt bombards fast enough with its tiny slash proc damage. Heat is okay, but its armor melt shouldn't matter if you're aiming to kill what you're shooting quickly, and thus before fire even melts enough armor (2 seconds for 50% is too long).

Quick math, with 28 pellets at 3.6% chance of status per pellet, the odds of something proccing is about 64% if all the pellets land (though realistically you might hit 20 pellets consistently, which is 52%). If we assign a quick estimation of the odds of viral, slash, or heat proccing when something does proc, it'd be about 40%/20%/40% respectively. If all pellets hit, the odds of viral proccing then is about 25% (64%*40%). That's a 25% chance of giving you double damage to health which blows the marginal damage boost you'd get for using [Maim] out of the water. Of course, if you have something else proccing viral for you (such as a sentinel or [Saryn]), then go nuts with slash+heat. I prefer to have viral built into my weapon however.

[Magnum Force]: Too much spread. 'Nuff sad.

If you do not have [Primed Heated Charge], use [Maim] instead. If you don't have [Maim], use [Augur Pact]. If you don't have [Augur Pact], go farm more mods.