Try the Crusader Pistol with the Pyro Receiver

[OranTruk]

I have been trying this out and this one works. 4 shots for a scorched (lvl50). Didn't have perk cards on. It is Explosive. It is "different" in that you get fire damage if you shoot something close. What you shoot, burns, then you can at least see them coming. 10mm ammo for flamer?
Crusader Pistol plans from Daily Ops or Minerva, Mods from Regs.
Pyro receiver
(Pyro) Target takes 5Fire/s for 5 seconds
Note: Counts as fire damage for Friendly Fire +5-15 Fire[1] – Gunsmith 3

But according to the Wiki;
Animations imply that the Crusader pistol is fed by a magazine housed ahead of the trigger, but the cryo and pyro receiver mods replace this with a futuristic component either loaded with a cryo cell or flamer fuel tank despite the pistol remaining chambered in 10mm cartridges when these mods are applied.

[insert food here]

Yeah Crusader is actually ok. Not great as it is still a pistol but it is the best of what we have.

The explosive effect will spread the elemental damage so explosive is best effect for this gun. I have a couple with good rolls but never got around to using them full time with a dedicated pistol build.

[Traveler]

It's ok with cryo. The problem is that pistol perks are in Agility and there are just way better uses for the points in that coulem.

[Mooman]

Side note or fun fact... not sure which... Long ago BGS was going to change the ammo type to match elemental effect, fuel for fire, cryo cells for cold.

They tested, they mentioned in live patch notes but the change never occurred in reality... They still use 10mm rounds...

It was a change and idea without any real meaning, ammo type has no bearing on weapon performance, it isn't coded that way.

[Straight White Male]

I just started putzing around with one myself & find it fun.

I'm playing as a Dirty Harry type with only the pistol.

I'm running the pyro, extended mag & long barrel.