[Montrala]

UHL works, however it has wery weak hammer spring. It has problem with moderately hard primers, not to mention really hard ones (surplus and Russian ammo).

For time being I recommend either JP or Wilson Combat. I will use CMMG 2-Stage on next 3Gun match (this Sunday) just to see how it works for me, but it is heavier than JP (I use JP with "tactical" hammer spring, for positive ignition) and has longer reset.

 

[Montrala]

Just FYI,

I had installed a Geissele SSF in one of our dept's Colt M16's some time back when we wanted a "marksman" type rifle in our inventory. I put my 416 upper on it for grins. I was getting very light primer hits with failures to fire about every 5th or 6th round. I tried my other 416 upper with this lower and was unable to get any rounds to fire as there was very light dimpling on the primer. Thus, I would not rate the stock SSF as a reliable option for the 416.

Updated. However listed were only special SSA version (that Geisselle offers for almost $400).

 

[Montrala]

Funny thing, I just heard about another trigger maker, that does not have HK compatible trigger with exactly same story, that I heard before: "Yes, we made batch of our triggers in HK version on special order for SOF unit, but we do not offer them".

 

[Montrala]

Updated:

ALG Defense ACT
ATC AR-Gold Trigger (needs fitting for MR223 due to rear receiver pin location)

 

[Montrala]

KAC two stage works.

Updated: KAC 2-stage.

Thank you.

 

[Montrala]

I have the Timney skeletonized trigger single stage 3 or 4 pounds (don't remember which one I ordered) I have never had any problems regarding the firing pin safety. The only problem I had was soft primer strikes with some xm193. I contacted Timney and they said that they could fix it. I mailed him the trigger on a Monday and he sent me a brand new trigger by Friday with a stronger spring. Haven't had a light primer strike since then. I love the customer service with them.

Updated with Timney then.

 

[Montrala]

TTU remarks reflected in first post.

 

[Montrala]

I did ask Wilson this exact question. They said the hammers are exactly the same.

But at least it looks like it can be made working. It is always easier to remove some material to fit, that add lacking part (like with Geissele). Recently I got Jard AK trigger that I needed to remove about 1mm from hammer face to let carrier slide over it in my Mini Beryl.

 

[Montrala]

So theoretically, one can just change to a stiffer hammer spring on a run of the mill mil-spec FCG & it will work for the 416. Has anyone try it?

I do not understand what do you have in mind. When FCG has hammer with right shape it will always work in 416 with mil-spec trigger spring.

It will work most of the time with "tactical" (JP red) hammer spring (I had problems of some 8% misfires on surplus ammo in temp -20C). It will also work with even with light spring (JP yellow) if primers are soft and hammer is light (like JP competition hammer).

 

[Montrala]

I am currently building two 416 uppers with two Bushmaster lowers (my state will only allow it this way...I am behind enemy lines). I will more than 95% of the time shooting mil surplus ammo when finish. Originally when I was following this thread, I was pretty much have my mind set on the Wilson TTU-3G trigger (2 of them) to take on the hard primers of the mil surplus ammo. The Wilson trigger is not cheap. So I was just wondering if I just replace the hammer spring on my mil spec trigger with the JP RED hammer spring that can handle the hard primers of mil ammo, then I would not have to spend all that money for the Wilson triggers. Another words, I want to go cheap if I could.

In that case try to go with ALG Defense ACT trigger and try JP Red hammer spring. Also JP Yellow trigger return spring - it reduces weight, without influence on hammer. I had problems with JP Red only in really low teperatures.

 

[Montrala]

Hello everybody. I am curious if the ALG QMS Trigger will work with the HK uppers? I got it in a package deal and was debating if I needed to pick up a different trigger set.

QMS is mil-spec trigger like ACT. No reason for it not to work.

 

[Montrala]

I can't even charge the bolt back after dry firing. I get the impression that the hammer sits too high and might not be able to clear the safety. I called Wilson and they were unaware of any issues, so my guy who did the build may have screwed something up unintentionally.

Interesting. It was guy from Wilson who confirmed that only TTU-3G works in HK rifles. Your hammer engages safety lever, but lever is at end of travel before hammer can hit firing pin. At the end you have safety lever fully up with hammer stuck under it. This holds your BCG. Also TTU and TTU-MIL have different hammers that TTU-M2 and TTU-3G (last two look similar, but seem not to be exactly same as well).

UPDATE: Geissele HK MR556 trigger added

 

[Montrala]

Game plan at this point is to just pop a Geissle SSA-E in and see where it goes. Thoughts?

It will not work with HK firing pin safety.

 

[Montrala]

Darn, I missed your post BEFORE I went and installed Geissle SSA-E. However, a club member loaned me his lower with a Stag hammer and it worked just fine.

Ok, so opinions of the "best tigger/hammer" from the list?

I have good experience with JP trigger and with CMMG 2-stage trigger (2-stage is better for precision shooting). Now I have Wilson TTU-3G, but did not use it enough to endorse it. Interesting option is AR-Gold Trigger*. It is 2-stage so good for precision, but also very short reset for fast shooting.

* - Officialy it is not HK compatible, but two my fiends used this trigger in their MR223 and it worked.

 

[Montrala]

Montrala, can you use any of those triggers and still use the safety when the hammer is uncocked (in generic lower)? I noticed that the Geissle HK MR556 works but you can't use the safety unless the hammer is cocked. Odd, not that one necessarily needs the safety while bench shooting.

Only original HK 2-stage trigger allows to put weapon of safe with hammer down. Once you start to change triggers, you loose this feature.

 

[Montrala]

Is that, perhaps, the reason why geissle made a separate hammer for HKs? Is it just this safety function? Because I've been using mine with a regular SSA for a while now. Has anyone said what the geissle HK specific hammer adds?

Separate hammer for HK in Geissele triggers is needed to work with automatic firing pin safety. It has nothing to do with manual safety.

 

[Montrala]

Not true. I've got the adjustable UHL match trigger (designed for MR308) which is compatible also in MR223A1 and you're able to put weapon on safe with a hammer down.

Wasn't aware of that. Anyway still not available for our US friends. Even if it was, they would never accept price.

BTW Did stronger hammer spring change trigger weight?

 

[Montrala]

Does the Geissele S3G trigger work with the HK MR556?

No. Look at list in first post..

 

[Montrala]

Does the MR556 run reliable with the yellow spring from the JP EZ-Trigger Kit?

I used yellow spring with "classic" JP trigger and had problems with light primer strikes in cold conditions (around -10C). When I used red spring (stronger than yellow, but still weaker than standard) I never had problems.