Posted on 09/10/2019 10:08:59 AM PDT by Black_Rifle_Gunsmith
This is for all the readers and commentors bookmarking my past AR-15 guides and discussions:
Last month, a few rifle builders on one of my forums asked questions about installing mil-spec and commercial buffer systems on their finished 80% lower units. One cited issues with their lower assembly install and the castle nut threads. Others weren't entirely sure about what either type of measurement specification represented. So, I wrote up a guide explaining the similarities and differences between the two.
Bookmark for later...
Thank you for posting this, brother! I try to keep up with everything that will help me to have well behaved and polite ARs. :-)
Very useful and simply described!
Good article - it laid out the facts very clearly.
I ran it by a buddy of mine who is an M16-family armorer. He verified that you ONLY want a true Mil-spec (not just mil-spec dimensions) buffer tube. IOW, you want the T-7075 aluminum. Here’s his explanation:
“So... why would you, a non military member and not a law enforcement officer need a MIL SPEC tube. Strength.... the proper way to clear a jammed AR 15 / M16 rifle is to collapse the stock to its shortest position and slam the butt on the ground. The inertia will cause the jammed action to open. Try that with a commercial tube and you will most likely break the tube.”
Slam the butt on a solid surface while pulling on the charging handle. I had ta do that quite a few times with a particularly tight Noveske chamber.
It works, but it's annoying to hafta do. d:^)
Timely post. I just replaced my buffer tube because I damaged it trying to remove it to replace and dremel/drill out a stuck buffer retaining pin.
Needless to say: DON’T use LocTite on the buffer threads!!
Mil-Spec
Buffer Tubes,
Preferred,,,
Thanks for
All the Good Info!
Early military buffer tubes (pre-M4 carbine) were “commercial” diameter. Colt apparently reduced the diameter of the M4 buffer tube to what we call “mil-spec”, for unspecified reasons. So, if you plan to use a ‘retro’ (pre-M4) military collapsible stock, plan on using a matching early “commercial” diameter buffer tube...
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