The same weapon type behaves differently depending on the map; each map has its own specific recoil, spread, configurations etc... For example, the hamr appears on several maps but with different settings. It seems the mod author included only a single config for the same weapon across all maps.
The hamr in origins, for instance, isn't using its original origins settings, it's likely using the tranzit config, the same applies to the rpd, which doesn't exist natively in origins, explaining why it's so inaccurate and buggy.
In short, this mod adds weapons but neglects their map-specific behavior, to fix this, the mod needs to load the correct weapon config for each map (if it exists) and manually adjust the attributes for added weapons, as each map uses its own variables to calculate weapon behavior.
//zone_dump\zone_raw\zm_transit\weapons\hamr_zm
adsViewKickPitchMin\-40
adsViewKickPitchMax\60
adsViewKickYawMin\-50
adsViewKickYawMax\50
adsViewKickCenterSpeed\1575
adsSpread\3
hipViewKickCenterSpeed\1575
//zone_dump\zone_raw\zm_tomb\weapons\hamr_zm
adsViewKickPitchMin\-30
adsViewKickPitchMax\55
adsViewKickYawMin\-30
adsViewKickYawMax\60
adsViewKickCenterSpeed\550
adsSpread\0
hipViewKickCenterSpeed\900