Short buffer tube

AR/M4 AR Technical Discussion
1

I need some expert help. A friend purchased a buffer tube at a local gun show and it had no packaging. When I put his lower together last night, I noticed something was wrong with the buffer tube. The seller told my friend it was a mil-spec tube and I tried two different stocks and they were extremely tight fitting. I had a Crapco-Tapco commercial stock laying around and it fit really loose. After comparing the tube to my other two rifles I noticed the tube was an inch shorter than the other two. I have 2 questions. What kind of tube or what is it made for, and will the bolt cycle correctly being 1" shorter? My friend took the lower home and I dont think he is going to try to fire the weapon until next weekend. Any feedback will help.

Thanks

2

Is this a carbine receiver extension or rifle?

If rifle, the shorter tube may be an “entry” length, which takes CAR spring and buffer.

Either way, always verify proper stroke length manually with the charging handle before shooting the first time.

The boltface should go to the rear of the ejection port and no more.

3

Its a carbine tube. 6 position tube.

4

Sounds like an unknown commercial CAR receiver extension.

5

An RE is too important a part to buy unpackaged at a gun show…

Throw it in the junk pile and order a decent one.

Even if it is “mil spec” dimensioned.