Newbie Question about 6.8mm

[4571]

I posted this in the general discussion also, but was told I might get better help here.

I have a dilema that a buddy has brought to me. He acquired an AR-15 from a relative that passed away. It is a DPMS .223/5.56, but has two magazines that are 6.8mm. There was also a letter with the gun that appears to be from the person that originaly sold the gun and there is references to it being 6.8mm. How can I tell if it is the .223/5.56 that is on the gun or the 6.8mm on the magazines? If it is 6.8mm can it be converted back to .223?, If so, what needs to be done? Any help is appreciated?

 

[bedlamite]

The difference between 5.56 and 6.8spc is the barrel, bolt and magazines, you can build a 6.8 on a 5.56 marked lower. Pull the bolt out, the cut out in the face will be about .430" for 6.8 and about .380" for 5.56. The barrel should be easy to see the difference, 6.8 uses a .277" barrel.

 

[bcrash15]

There should be a marking stamped on the metal barrel itself somewhere that indicates what the chamber is, is that the one you are looking at? If by "on the gun" you mean the lower, that is not necessarily what the gun is like bedlamite said, and if it turns out to be 6.8 you should probably figure out a way to clearly indicate it is not 5.56 (strike it out, etc) for future reference by all. If you have access to a 6.8 or 5.56 round you can swing the lower open and drop it in the chamber to see how well it fits, with the caliber difference it should be pretty obvious if one is not right.