I think the double barrel would be a great idea, too. But I recognise the difficulty putting it in, especially having to nerf it for the fact that it's so strong.

I think a decent way to resolve this - even though it doesn't quite match up with the narrative of the thread - is to perhaps place it as an extremely rare drop from a weapon's case. Given the current mass-availability of orbs and virtually everything else from Weps Cases, it might be interesting to add weapons that we believed were OP there. Therefore, you're not giving everyone a bonafied kill weapon every time they go Weapons Dealer.

As for that, though - I'd say Intervention, Honey Badger (I remember when they were a myth on ZARP).
Also, fists would be a very fun addition. Fists might allow for an alternative to gun fights out in the streets and reduce the risk of "accidental RDM" from them.

If I may also suggest some that aren't necessarily M9K but might be viable additions.
Dual pistols, they'd look cool, and it'd likely be a matter of accuracy sacrificed for greater ammo/power.
Duelling pistols are another, too. Like, *really* low ammo (maybe even like one or two bullets) but supremely powerful. Though, again, raises the issue of OP weapons. Could put a holster/drop timer on them or more rare drops (seasonal case, maybe?)
Laser/plasma weaponry might offer not only more interesting weapons, but might also allow for a deeper look into the narrative of GenCorp without having to get a case. Again, perhaps a damage cap/nerf may be needed...

Anyway, apologies for all the off-M9k suggestions, but I hope they prompt or pique interest.

I think the double barrel would be a great idea, too. But I recognise the difficulty putting it in, especially having to nerf it for the fact that it's so strong. I think a decent way to resolve this - even though it doesn't quite match up with the narrative of the thread - is to perhaps place it as an extremely rare drop from a weapon's case. Given the current mass-availability of orbs and virtually everything else from Weps Cases, it might be interesting to add weapons that we believed were OP there. Therefore, you're not giving everyone a bonafied kill weapon every time they go Weapons Dealer. As for that, though - I'd say Intervention, Honey Badger (I remember when they were a myth on ZARP). Also, fists would be a very fun addition. Fists might allow for an alternative to gun fights out in the streets and reduce the risk of "accidental RDM" from them. If I may also suggest some that aren't necessarily M9K but might be viable additions. Dual pistols, they'd look cool, and it'd likely be a matter of accuracy sacrificed for greater ammo/power. Duelling pistols are another, too. Like, *really* low ammo (maybe even like one or two bullets) but supremely powerful. Though, again, raises the issue of OP weapons. Could put a holster/drop timer on them or more rare drops (seasonal case, maybe?) Laser/plasma weaponry might offer not only more interesting weapons, but might also allow for a deeper look into the narrative of GenCorp without having to get a case. Again, perhaps a damage cap/nerf may be needed... Anyway, apologies for all the off-M9k suggestions, but I hope they prompt or pique interest.