KAC Ambi Safety -- on safe, lets hammer fall, not fire

[CubeWarrior]

Hi,

Just wondering if anyone else has had this issue. I installed a KAC ambi-safety on an SR15 factory lower (non-ambi). Looking from directly above the receiver so i can see into the trigger group and both sides of the safety levers at once, my factory SR15 has a third a millimeter gap between the safety lever and the lower receiver's faces. My newly installed ambi safety retained just over a half millimeter gap between the safety lever and the receiver face (a little more than twice that of the factory gun). My factory SR15 safety has a little play in it (ability to slide it left to right side within the receiver), and my SR25 has none. The safety I installed had more play--to the point where I could definitely push it in on one side and feel it on the other side.

Function check revealed that if I put +10lbs on the trigger in safe, the hammer would release. At normal trigger squeeze, rifle functions as it should. At the range, the same condition would release the hammer fully forward. There were no primer strikes and the rifle would not fire when the hammer released from safe. Trigger/disconnect, etc. were working as they should. Rifle fired as it should. If I pushed the installed safety lever against either face of the lower receiver would enable proper function check without allowing the hammer to fall. I believe everything was tightened and installed correctly accept for the gap with the safety. I'm assuming that the lateral play in the safety was just enough to misalign the notch that holds the back of the trigger--causing malfunction. When I removed the safety, everything appeared to be machined correctly, so I don't know what exactly was allowing the back of the trigger the clearance it needed to release the hammer.

I installed a CMMG single sided safety, and the rifle function checks.

So, two questions:
1) Has anyone seen a similar issue? (I'm still trying to visualize how a little lateral slop would create any vertical clearance issue for the rolling cam and rear of the trigger)
2) Are there different types of KAC ambi safeties? My installed ambi safety was the same as IWS receivers, but the receiver I installed was the older style.


Thanks

[JoshNC]

Sounds like you should contact KAC CS.

[CubeWarrior]

Sounds like you should contact KAC CS.

I'm going to -- this post is by no means a complaint against KAC. My AR platforms are strictly KAC. My first thought was that there are different safeties for the new receivers versus the older ones, and that I missed the differences. That said, I'm at a loss at how horizontal play within the safety lever would have anything to do with the vertical camming action of the safety against back of the trigger.

[Failure2Stop]

Well, that's new.
Please hit up our CS at returnsandrepairs@knightarmco.com and we'll get you squared away.