How do I Identify AR-15 Upper and Barrel?

pauldg · May 16, 2011

Greetings all,

I just "horsetraded" for an AR-15.. Never had one before, figured I needed one for the collection.

I know the upper and barrel are not the same maufacturer as the lower. I was told the upper and barrel are a CMMG, 5.56 cal, with a chrome lined 1 in 7 twist. How would I verify this? I removed the handguards, and cannot see any engraving on the barrel. I have not taken anything else apart to look elsewhere yet.

Thanks much,

PaulG

Cemetery21 · May 16, 2011

If the barrel is unmarked, at least you can verify the twist rate.
With a tight patch on a cleaning rod and the patch holder just started in the barrel, put a piece of tape on the rod measured 12" up from the rear of the receiver. Let the ends of the tape stick out to make a "flag". Note the position of the flag and push the rod in until the flag rotates around to the same place. Measure again and the difference is your twist rate, e.g. 1 turn in 7", 1 turn in 9", etc.
If the barrel is marked, it is usually just in front of the front sight base, sometimes on the bottom, sometimes on the top.

herd48 · May 16, 2011

Cmmg barrels that I have seen were clearly marked on bottom of barrel under handguards.

TerryMathews · May 16, 2011

Not all CMMG barrels are. I've got a MedCon profile barrel that is completely unmarked.

1saxman · May 20, 2011

Take another look at the underside of the barrel under the hand guard in broad daylight. The stamping may be very light and filled in with Parkerizing, but it's there.

TerryMathews · May 21, 2011

I just checked every visible inch with a 300 lumen flashlight. If the barrel is stamped, its under the fsb or barrel nut.

I've read about CMMGs rarely not being marked, over at arfcom.

How do I Identify AR-15 Upper and Barrel?

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