Hi,

I have a 20" AR15 type Hbar barrel here and it is missing the locating pin that makes sure that it is indexed to the upper receiver properly.  There is a hole in the correct spot.  Where would I get one of these pins or do I make one?  Also how are they fitted, press fit? Thanks for any help.

Look at the hole, and bee sure it is bored down into the barrel a little bit, so as to lock together via the pin.

As to the pin, a black 1/8" diameter roll pin will suffice (might cost you 25 cents?), get one that is 1/2" long or so, tap it into the hole, and finish with a file.

At this time the hole is not cut into the barrel at all.  I can see the threding on the barrel in the hole.  I should drill into the barrel a bit so that the pin locks the barrel and the extension together?  Thanks.

The hole is only in the extension, the hole is drilled in the extension before the extension is installed on the barrel.

The pins are standard steel dowel pins of the correct length and diameter.

What make of barrel and why don't you contact the maker about returns/replacement/repair/parts?

The barrel is a bit of a noname special, ie. cheap and has no markings though is looks good for a plinker which is all I'm looking to get out of it.  Thanks for the info.

I wouldn't recommend using a roll pin. The proper pin is solid, and hardened.

Also, I wouldn't drill the hole into the barrel threads. No need to do that. The extension is never going to move from its present position.

Thanks for the advice guys :)

You need to read the article from The American Rifleman magazine titled "Match Heavy Barrel Enhances AR-15 Accuracy" where they wrote up the USMC armorers at Quantico built Match barrels for M16 from blank..... Though it states to use "drill rod" for the pin, there is no load on that pin, it just sits in the uppers' slot to keep barrel from turning in the upper.

Also stated in the article-- [blue]"Use the hole in the extension as a guide to drill about .010" into the barrel, so that when the new pin is in place, it will prevent loosening of the extension".[/blue]

I also bought a couple of 20" fluted bbls (from Northridge Intl) that had no locating pin.

I used a piece cut from the shank of a 1/8" drill bit. It was a press fit in the hole, then I filed it to correct height.

Be sure you check headspace. I wanted Mil-Spec, so I used an armorers Go-Nogo gauge to check.