Hello everyone, 

I'm new to the forum, but I am trying to gain some information from HK416 (Upper) users.

I recently acquired a AF Date code 10.4 416 upper. In most of my reading I am hearing that the system beats itself to death with use with a suppressor, especially the KAC NT4, which kind of surprises me.

To my question, can anyone here shed some light on what they did to mitigate the large amount of back pressure this setup is supposed to create. I wont be able to get out to the range for a bit, so i'm trying to be proactive in the mean time.

I have already ordered a Vltor A5 Tube, Spring-co Green Spring and a A5H3 buffer. I gained that information from here in an older post. 

Sorry to be long winded, but if has anything to add, Id love to hear it. 


Original Post

Well you might find more info over on HKPRO? I have a 10.4 upper with the 10" non adjustable GB & a 14.5" A5 upper with adjustable GB, while I don't run suppressed I still use the standard HK spring, which in my understanding can handle suppressed fire? having said that, I have read that some guns with the non adjustable GB may not run suppressed, however that could be an ammo or suppressor issue? 

Good luck , Cheers 

Certified Glock, S&W, SIG  Armourer

Colt, REM Armourer

Buy a HK Vented 10” gas block. There are some out there but be careful of the HKParts knock offs. You want made in Germany HK vented block. Or you can use the 14.5”/16” vented block.


With either block you’ll have to have the bore of the barrel gas vent into the gas block modified. If you do it, you’ll be right as rain. I have 3 uppers done this way (but used the 10” vented block). 


Do this and there will be no need to mess with springs and shit. 

“When sorrows come,

they come not single spies

but in Batallions.” Claudius -WS-

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