I've got one, and is the single biggest improvement for the AR system I have installed. However I have not had the problem with the safety/selector as mine are just for right handed shooters.
If the outside width of the trigger is a bit large and appears to bind inside the slot/notch of the safety, it wouldn't be a big deal to open it up a bit. There are no real concerns for case hardening, or pressure, etc similar to "polishing" a trigger/hammer engagement. In those areas there is the depth of hardening to be concerned with. Not so in the safety area.
Also the safeties aren't that big of a money investment as compared to the KAC triggers, so grind/file/dremel away till it fits and works.
At least that my opinion.
If the outside width of the trigger is a bit large and appears to bind inside the slot/notch of the safety, it wouldn't be a big deal to open it up a bit. There are no real concerns for case hardening, or pressure, etc similar to "polishing" a trigger/hammer engagement. In those areas there is the depth of hardening to be concerned with. Not so in the safety area.
Also the safeties aren't that big of a money investment as compared to the KAC triggers, so grind/file/dremel away till it fits and works.
At least that my opinion.
