extension tube specs

[Waylander]

Could somebody tell me where I can locate specs on the stock extension tube? Do you need the end plate/castle nut to keep any of the lower parts in place? I think there's a spring in the back of the lower receiver that the plate keeps in place but I'm not sure.

[fdxpilot]

Could somebody tell me where I can locate specs on the stock extension tube? Do you need the end plate/castle nut to keep any of the lower parts in place? I think there's a spring in the back of the lower receiver that the plate keeps in place but I'm not sure.

This Magpul document has the specs for Mil-spec and commercial sized extensions:

http://magpul.com/pdfs/technotes/ctr/buffertubeid.pdf

And yes, you need and endplate or one of the various replacements that incorporate a sling mount to keep that takedown pin spring in place.

[ge_traveler]

Another thread on the same topic.

https://www.m4carbine.net/showthread.php?p=309293

[Iraqgunz]

The tube, castle nut and endplate keep two things in place. The tube holds your buffer detent spring and pin in place and the castle nut and endplate keeps your rear take down detent spring and pin in place.


Could somebody tell me where I can locate specs on the stock extension tube? Do you need the end plate/castle nut to keep any of the lower parts in place? I think there's a spring in the back of the lower receiver that the plate keeps in place but I'm not sure.

[Waylander]

I couldn't get the link to work so I went to the support site and found the spec drawing http://store.magpul.com/downloads/Receiver_Extension_Milspec_M4.pdf

I may not be looking at it right but does the castle nut part have a different diameter/thread than the receiver part or are the peaks just flattened?

edit:
Nevermind. I found the link on the other topic.