If you are a first-time maker of gun construction and buying all the parts of a gun but you come across a lot of buffer tubes. Buffer tube also called receiver extension, and it’s a cylindrical aluminum accommodation that contains a recoil spring and an AR-15 buffer. Buffer tube acts as an organizing point for a gunstock.
Buffer tubes can be a mil-spec or commercial, and so. If you own a black rifle and are worried that How to Tell If Your Buffer Tube Is a Mil-Spec? The external diameter of the tube’s stock-end will easily tell you what type of buffer tube you buy.
How to Tell If a Buffer Is Mil Spec?
The mil spec buffer tube contains 1.14 diameter at the end of a gunstock. And the diameter at the receiver end is 1.185 with the thread height.
The commercial buffer tube contains 1.17 diameter at the end of a gunstock. And the diameter at the receiver end is 1.170 with the thread height.
So, there is the only difference of outer diameters between the mil spec and commercial buffer tube. To tell about what type of buffer you have. For this, you just need a micrometer or a caliper to measure the outer diameter of a buffer tube.
From the top of the cord screws, the mil-spec lowered, and most of the back thread of a mil-spec reduced slightly. Also, the mil-spec tube is square from the back end. And the commercial tube has the same diameter from the top of the cord screws, and the back end of this tube has a slight angle of 5-degree.
If you have a mil-spec buffer tube, then the outer diameter of your buffer tube must be measured at about 1.14. After measuring when you get the result of an outer diameter of about 1.14, then you can tell that your buffer tube is mil-spec.
There is a measured diameter difference between is 0.024, and because of this difference, you can never put a mil-spec slider on a commercial buffer tube, or vice versa, it can cause damages.