HKPRO Forums banner

1 - 15 of 15 Posts

·
Registered
Joined
·
83 Posts
Discussion Starter #1
So not to sure why but after looking at it I do like the look of an extended castle nut not sure why but its a good look but a little birdie told me that the HK extended castle nut has a proprietary thread pitch? So if Im hearing that right it wouldnt be able to use regular buffer tube/ receiver extensions? Does the extended castle nut impact LOP? or would I still need a receiver extension? Thank ahead of time
 

·
Banned
Joined
·
2,011 Posts
So not to sure why but after looking at it I do like the look of an extended castle nut not sure why but its a good look but a little birdie told me that the HK extended castle nut has a proprietary thread pitch? So if Im hearing that right it wouldnt be able to use regular buffer tube/ receiver extensions? Does the extended castle nut impact LOP? or would I still need a receiver extension? Thank ahead of time
It's not proprietary it just doesn't fit properly on a Commercial Buffer tube, but (as stated below now) does on the Mil Spec Tube which is what is present on the HK 416 A5. Ask UMP45entry.. He mentioned to possibly having to have threads milled off inside castle nut to work on (what I now know was) a Commercial buffer tube about halfway across inside of Nut..

It had been a long time since our discussion and I could not remember how he ended up resolving the issue..
 

·
Premium Member
Joined
·
957 Posts
I have a couple of these new A5 castle nuts on my rifles, I love them. They do not fit on the commercial buffer tubes but fit right on the mil-spec tubes as that's what the A5 uses.
 

·
Premium Member
Joined
·
957 Posts
Been awhile I couldn't remember what you had done!!
Yeah, when I first got them I tried to install it on a commercial tube and didn't have a mil-spec tube floating around. I did eventually get it to work with the commercial tube by boring out the rear of the nut to fit over the commercial threads and tube. Just grab a mil-spec tube and you're good to go.
 

·
Registered
Joined
·
3,161 Posts
Am I crazy, don't the MR556s come with mil spec tubes?


Sent from my iPhone using Tapatalk
 

·
The Librarian
MP5-N and HK23E-K
Joined
·
5,425 Posts
I'm pretty sure it's a commercial tube.
 

·
The Librarian
MP5-N and HK23E-K
Joined
·
5,425 Posts
I've always found it rather strange why HK wouldn't go with a commercial tube, but than again we don't want to confuse it with the HK416.
 

·
Registered
Joined
·
3,161 Posts
This is s great thread. I think it needs to go into the library or become a sticky.

Mods, oh Mods where are you Mods???


Sent from my iPhone using Tapatalk
 

·
The Librarian
MP5-N and HK23E-K
Joined
·
5,425 Posts
Or added to the FAQ thread that PB started.
 

·
Registered
Joined
·
3,161 Posts
So I am bringing this back to life because I ordered a milspac HK buffer tube and received it.

These A5 extended castle nuts fit perfect on it. It does appear that the back half of the castle nut threads are shorter than the front half. It sails right over the unthreaded buffer tube.

The funny thing is, it's identical to the MR and CR556 lower buffer tubes that I have on all my 416 upper/556 lower rifles.

Now I've got to send my lowers to James @Marine0303 to have them installed.
 
1 - 15 of 15 Posts
Top