When you have JTAG you can try change the skills here a sample from Logen try change from -0.1 to +0.1 or to 0:
<skill id="FirearmsApprenticeLogan" cat="Tree2" max_level="1" tier="6">
<tier_req tier="5" cat="Tree2" value="3"/>
<effect id="FireWeaponsSkill" change="1"/>
<effect id="BulletReloadSpeed" change="-0.1"/>
<effect id="BulletCriticalDmgMul" change="0.05"/>
<effect id="BulletCriticalChance" change="0.05"/>
<effect id="BulletAccuracyFactor" change="0.1"/>
<effect id="BulletRecoilFactor" change="0.05"/>
<effect id="FirearmsMoveAccuracyReduce" change="-0.1"/>
<effect id="StomperSkillLevel" change="1"/>
</skill>