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wildcard
12-07-2006, 1:23 PM
I think I just learned something new about AR-15 barrels but I can't find a clear description or definitive confirmation. Is a "barrel extension" the star shaped area (includes the ramps) where the catridges are fed and extracted? If yes, then what is a left handed barrel extension? It looks rather symmetrical to me.

I never knew a standard barrel consisted of two pieces.. it looks like a single piece to my untrained eye..

JPglee1
12-07-2006, 1:32 PM
I think I just learned something new about AR-15 barrels but I can't find a clear description or definitive confirmation. Is a "barrel extension" the star shaped area (includes the ramps) where the catridges are fed and extracted? If yes, then what is a left handed barrel extension? It looks rather symmetrical to me.

I never knew a standard barrel consisted of two pieces.. it looks like a single piece to my untrained eye..

Yes, thats the barrel extension. It threads to the receiver and then the barrel threads onto it.


Im guessing a left hand version would be somehow cut to extract/eject off to the left?


JP

mltrading
12-07-2006, 1:35 PM
I think I just learned something new about AR-15 barrels but I can't find a clear description or definitive confirmation. Is a "barrel extension" the star shaped area (includes the ramps) where the catridges are fed and extracted? If yes, then what is a left handed barrel extension? It looks rather symmetrical to me.

I never knew a standard barrel consisted of two pieces.. it looks like a single piece to my untrained eye..


1) The star-shape slots are for the locking lugs of bolt. They are part of the locking mechanism.

2) There are two feed ramps because the rounds in the magazine are double-stacked. While feeding, the cartridge would be loaded from either right or left, alternatively.

3) Are there LH BBL extensions? I doubt it. The RH/LH configuration is determined by the extractor on the bolt (and ejection port, of course). It's nothing to do with the BBL extension.

bwiese
12-07-2006, 1:51 PM
Yup, AR bbls are 3 piece - barrel, gas block with/without front sight, and the barrel extension.

If you get a bbl, ou normally buy all 3 together, preassembled & headspaced.

The bbl extension's relationship to the bbl & bolt determines headspacing, and not its mounting to the upper receiver. When you buy a quality bbl, it should already be headspaced for a quality bolt.

It's a ***** to remove the bbl extension. There are special wrenches, but some folks just adapt old used bolts and fashion this into a homemade AR bbl wrench.

I don't think there are lefthanded bbl extensions. I think regular AR bbls+extensions work fine in left-handed rifles like Stag -L models. They use a different bolt instead.

wildcard
12-07-2006, 2:19 PM
Yeah, never realized the barrel extension and the barrel were two seperate pieces. Here's what got me thinking:

Advertises an "ambidextrous extension"
http://www.rainierarms.com/?page=shop/detail&product_id=446

Requires the use of a "ambi-extension"
http://www.rainierarms.com/?page=shop/detail&product_id=192

Has for sale an "ambi-barrel extension"
http://store.stagarms.com/catalog/product_info.php?products_id=65&osCsid=76a1a84b4006523949b3e71755549ddf

I errored in calling it a left handed barrel extension earlier. I'm not left handed but was just looking at what makes them different aside from the obvious to satisfy my own curiosity.

What's the difference between a "ambi-extension" and a standard extension which looks rather symmetrical? Marketing?

bwiese
12-07-2006, 2:32 PM
Hmm, maybe there is some difference in extensions.

If Stag has an ambi-extension, there's a reason for it...

mltrading
12-07-2006, 3:05 PM
Why not asking STAG for the meaning of "Ambi BBL extension"?

TheMan
12-07-2006, 5:05 PM
I don't think there are lefthanded bbl extensions. I think regular AR bbls+extensions work fine in left-handed rifles like Stag -L models. They use a different bolt instead.

Stag sells ambi barrel extensions. There have been pics posted of the difference. Basically, standard barrel extensions have the locking lugs chamfered to make it easier to lock/unlock, but only one side of the lug to how a standard bolt locks up. Since the left handed bolt carrier makes the bolt twist in the opposite direction, the ambi extensions have this chamfer on BOTH sides, so it would work with bolts that cam in either direction.

The Stag L models also use standard bolts, not different bolts like you mention. They do have non standard left handed carriers though.

Edited to add a pic link found on ARFCOM. This is a cut up Stag barrel extension, with chamfering on both sides of the lugs

http://home.comcast.net/~c.duarte/ambiext.jpg

mltrading
12-07-2006, 10:04 PM
Stag sells ambi barrel extensions. There have been pics posted of the difference. Basically, standard barrel extensions have the locking lugs chamfered to make it easier to lock/unlock, but only one side of the lug to how a standard bolt locks up. Since the left handed bolt carrier makes the bolt twist in the opposite direction, the ambi extensions have this chamfer on BOTH sides, so it would work with bolts that cam in either direction.

The Stag L models also use standard bolts, not different bolts like you mention. They do have non standard left handed carriers though.

Edited to add a pic link found on ARFCOM. This is a cut up Stag barrel extension, with chamfering on both sides of the lugs

http://home.comcast.net/~c.duarte/ambiext.jpg

Thanks, man. Learn something new.:)