Primed Chamber appears to simply double your total damage regardless of magazine size, fire rate, or reload speed. Considering the mod was just made available to the entire community for the first time ever, it's likely going to be an extremely popular pick for builds in the coming weeks.
True Steel, Sacrificial Steel, Blood Rush, Maiming Strike, and Weeping Wounds still have their old values, meaning that most if not all melee builds are completely outdated. Also melee combo counter now goes up to 12x. IMHO updating these stats should have a higher priority than adding a handful of new weapons given the larger impact to builds.