Will work with hk mr556 a4 with modified safety axle - Geissele Hk Mr 5.56 Trigger

Since writing my previous review, I have purchased the HK MR556 A4, and installed this trigger along with the Haus Tool 'SELECTOR AXLE HK MR95 HAUS'. All features of the A4 remain operational with the exception that I cannot SAFE the gun unless hammer is cocked. Short throw feature of the safety lever is retained.
I am more enthusiastic about the trigger now that I have additional experience with it. It is a true two stage trigger, but there is no 'click' as might be expected. The first stage requires a 3.5 lb. pull, then a wall is reached. The second stage requires only a 1 lb pull. The release characteristics are excellent. Of course it is possible to simply pull through both stages completely to release the hammer.
I used a 1/16" pin punch to drive out the pin from one safety lever. Once the axle was removed from the receiver, I used a piece of soft pine board with a 3/16" hole drilled to receive the driven out pin of the other safety lever. The pin punch had to be pounded straight several times during this process. Along with the 'SELECTOR AXLE', I also purchased the 'Maritime Pins' for reinstalling the safety levers. I used a larger punch when driving these pins until flush with the edge of the safety lever, then evened them up with the 1/16" punch. BTW, removing the original trigger, and installing the new is easier while the safety axle is out of the receiver.
It might be possible to remove the HK Selector Axle and modify it using a Dremel tool. The $50.00 I spent for the Haus version seemed the simpler solution.Something about having modified parts in an HK product didn't sit well with me.

Bottom line - buy this trigger, you won't regret it.