Wrong gun then? There was a few faction weapons, one was Culling I think, there was a dead orbit hand canon, had a red hand IX but didn't like the roll. I've gotten a lot of purple weapons from nightfall - I'll check the stats & if it isn't a roll that I'll find useful they usually end up as shards. Cryptarch has been a bit nicer to me lately, I've gotten a solar & a void Longbow, both with firefly (firefly standard on that weapon?)