HK MR556 A4 Update 2

[@RetropPM]

Thanks for these videos, a great thing for the HK community to have these insights in-advance so we can avoid mistakes and wasted money on parts down the road.

[@HKShootingwithDerekG]

Thanks so much!

[@Elitheiceman101]

Chrome dome checking in lol thanks for the update. 👍

[@HKShootingwithDerekG]

😂😂

[@tomgun7341]

The trigger you've installed is a Wilson Combat TTU-3G. For sure :) The TTU-3G will engage the firing pin safety on HK MR rifles.

[@HKShootingwithDerekG]

well done!!! The best trigger, in my opinion, available for the MR.......absolutely outstanding

[@texture6]

The Stag Arms Model 8 has been running solid

[@JoeWinter-ky8xo]

I love HK, but that love when it comes to their long guns is pretty much reserved to the roller locks

[@HKShootingwithDerekG]

@@JoeWinter-ky8xo MP5 is my favorite of all!

[@DirtyEpic129]

Does the Geissele trigger made for the HK MR556A1 drop into this one without issue?

[@HKShootingwithDerekG]

I still have not tried to put one in an A4 but I have every reason to believe it will work fine with the 45 degree selector

[@ketokyle2412]

It will not work.I'll just try it tonight. Geissele hk 05-220. No go

[@han1075]

Thanks for the uploads! I'll be getting one shortly. What muzzle brake did you use? Also, does HK use Rocksett or Locktite on the factory A2 flash hider? I'm about to also upgrade the flash hider on my MR762 to a muzzle brake/comp and wanted to know how much I'll have to fight to get the factory flash hiders off. Thanks!

[@HKShootingwithDerekG]

I don’t know yet for sure which muzzle locking compound. You should invest in reaction rods for muzzle device changes as they make the task a breeze.

[@han1075]

@@HKShootingwithDerekG Thanks. Did you heat or soak the flash hider in warm water prior to removing it? My MR762 does appear to have "something" on the threads, but not sure what it is either.

[@HKShootingwithDerekG]

@ ​​⁠I just used heat and came right off…. Try some heat, cheers

[@g47k]

Does the gun also come to europe the a4 does make the gun realy good for competition a1 is over gased and front heavy.

[@ketokyle2412]

I got the HK mr556A4 didnt like the trigger. Ordered the Geissele 05‐220 mr 556 trigger. IT WILL NOT WITH THE 45 DEGREE SAFETY THAT COMES WITH IT. THERE IS A TINY NOTCH ON THE LEFT SIDE THAT DONT LET THE TRIGGER COME UP FAR ENOUGH.

[@HKShootingwithDerekG]

@@ketokyle2412 thx for sharing

[@rambdabamb4104]

really cool gun, HK quality as always, but i much prefer the HK416D A1/A2 model. its a hard pass for me as a collector. ill be sticking to my MR556A1. M27 IAR is the real deal!.

[@HKShootingwithDerekG]

Sure….you’ll end up with one

[@RAWPnS]

I was considering this rifle for my 11.5 but I have a sig spear lt 16,and the folding stock and about a G less ima get another spear.

[@bigred06100]

What ammo do you shoot mostly 55g, 62g or 77g

[@HKShootingwithDerekG]

Without a doubt 55 grain….77 is saved for over 300 accuracy

[@305gangsta777]

Boss man do all the previous HK Rails fit the new A4? For example the quad rail for 10.5 or the geissele super modular rail for Mr556a1 fit this new one?

[@HKShootingwithDerekG]

yes sir!

[@305gangsta777]

@ thanks for the response that’s great news

[@MieseRinde-n6i]

Will the HK MR556 A4 also be released in Germany?

[@HKShootingwithDerekG]

I have heard nothing about that

[@rambdabamb4104]

no reason to, the MR223A3 is the same or better if anything. they are both civilian variants of the A5 configuration.

[@HKShootingwithDerekG]

@ ​​⁠agree, would be redundant

[@Chevydude1982]

what trigger r u using? if u can say,if not no worries.

[@HKShootingwithDerekG]

@@Chevydude1982 top secret!!! haha, just keeping the trigger conversation specifics light on purpose. I don’t have all the triggers that are compatible with the MR556 so with the 45 degree selector throwing a new wrench in the mix, I figure I’ll let folks do their own testing and playing before I sway other’s discovery with my own findings. Again, for anyone reading, the 45 degree safety may cause trigger compatibility issues but overall not a big deal at all.

[@Chevydude1982]

@@HKShootingwithDerekG i figured cause u probably would of said it in ur video. no worries. awesome video. glad i found ur channel.

[@AggiePhil]

Due to the markings, I personally would not want to switch to a 90°.

[@HKShootingwithDerekG]

@@AggiePhil the gun is perfectly fine out of the box!

[@Blazerghost]

I swear I’ve seen over 100 comments about “iTs NoT ChRoMe LinEd.” Absolute smooth brains.

[@HKShootingwithDerekG]

Chrome Domers!

[@medieval_flail]

Maybe HK should try listening to consumers for once

[@FULLASSAULTChannel]

People want that feature because the MR223 & military version both have it without any accuracy issues. It’s easier to clean, it lasts longer and is more corrosion resistant. The ONLY reason it’s not offered is it cuts into the profit margin It has nothing to do with the accuracy . If you want to see the real smooth brains look at all the nut huggers falling for the marketing BS.

[@Chevydude1982]

i dont like 45 deg selectors. there is no point and most arent even safe. thats y theyre banned from being used in service carbines. u r not fast enough to notice a speed difference between a 45 and 90 deg selector. its a fix for a non existent problem.

[@HKShootingwithDerekG]

@@Chevydude1982 a fix for a non existent problem was my take long ago when many were going ga ga over them…..I agree

[@JeffPatrosso]

Chrome domers…. lol