28 March 2012

List of triggers that work with HK416, MR556A1 or MR223

This question comes back every so often. I decided to try collecting list of trigger groups that work with HK firing pin safety, so can be used either in lower other than HK or dropped into HK lower. Looks like most M16/M4 select fire triggers work with it, so list is of semi-auto triggers. Please take in mind that HK firing pin safety takes some hammer energy to disengage. Using very light trigger setup with light hammer springs can lead to light primer strikers on some brands of ammo (surplus, Russian, etc.):

ALG Defense ACT
Armalite National Match 2-stage
ATC AR-Gold Trigger (needs fitting for MR223 due to rear receiver pin location)
CMMG Gen2 2-stage
Franklin Armory Binary Firing System III (BFS III)
JP Competition Trigger
JP EZ Trigger
Geisselle HK MR556
KAC 2-stage
RRA National Match 2-stage (CAUTION: Only new version with rounded hammer is compatible)
Timney AR-15 Skeletonized
UHL Trigger (German made)
Wilson Combat TTU-3G and TTU-M2

I will try to update this list when new info will come in. Please give confirmed info on other triggers, I will update list.

WARNING: Some triggers will not work properly with HK safety from 2-stage "European" trigger (one that allows to be put on safe with hammer down). Old style HK safety or aftermarket safety may be necessary.


Geisselle SSF - standard model reported not to work reliably with HK416, special model required.

Last update 27th of Dec 2017 (BSF III added)


  1. Anonymous2/2/12 00:46

    Hi, what is lifetime for MR223 barrel?

    1. Depends of what you expect. I expect at least 25,000+ rounds with no measurable degradation of accuracy.

      What is lifetime? Probably you can shoot even 100,000 rounds and still have decent accuracy, but only time will tell.

      This expectation is based on known performance of HK416 barrels and SL-8 civilian barrels. However I only have shot 6,000 rounds with one. YRMV

  2. Will timney competition work ? or just the timney skeetonized ? they both appear to look the same.

  3. There are 2 important factors for trigger system to work with HK firing pin safety. First is hammer height and shape, that must be able to lift firing pin safety lever up. Second is hammer spring weight, that must have enough force to deactivate safety and fire a round. If hammer is same, first important thing is covered, then there is only question if spring is strong enough.

  4. Hey there,
    which of these triggers that you have list, have you actually used and which is your favorite.

    1. I used for some decent amount of rounds (at least 1000 or more) JP Competition Trigger (with JP hammer), CMMG Gen2 2-stage trigger and Wilson Combat TTU-3G. I also tested with limited number of rounds UHL and AR-Gold. My favorite is ... CMMG Gen2 2-Stage. I modified it to reduce take up, overtravel and second stage weight (reduced it). I use reduced power trigger return spring (but not as light as JP yellow spring) and extra power hammer spring. It still has well defined first stage, but also short reset and positive reset (I like very positive reset). Weight is around 3.5lb. It just fits me best from what I tried. It is not best "speed trigger" or best "precision trigger" but with my mods it is decent "all rounder". It also was not expensive at some $120 or so.