Posted: 7/16/2007 7:13:47 AM EDT
|
Are there any problems with using a different barrel extension than what came factory?....I've heard both sides to this issue. Some say that head space is critical on AR's and you need the orginal extension that came with the rifle. I've also read that the headspace issue on AR's is overblown, and that any stock parts properly tightened down will headspace just fine (this article said not to even worry about go/no-go gauges). What say you? |
| Is there something wrong with the extension that came with your barrel? Or are you just wanting factory M4 feedramps or something? Just curious. I don't have the answer to your question, sorry. I figure they would be on the barrel pretty damn well and would be difficult to swap. |
This is generally true. As I understand it, the gas port in the barrel is drilled AFTER the barrel extension is installed. This ensures that the the gas port is at the top of the barrel when installed, not indexed off to the side somewhere. The barrel extension is also critical to the headspace. I have never known an AR barrel to be sold without the extension - they are generally considered a unit and not to be separated. |
| I asked Frank White of CLE the same question. I had picked up a douglas spr barrel for a song but the problem was that it had the rifle extensions. So I asked him is it possible to change the extensions..he said no. Too much time and work. What could do was modify the rifle extension and cut the m4 ramps into it ...thus making it into a m4 feed ramped one. I went that route and it turned out great. The cost was like 20 dollars if i recall too. |
get a dremel and make your own! Look here |
|
The problem is that the thread timing is not likely going to allow you to tighten up to 150 ft-lb, and have it line up with the gas port AND have the correct headspace. So, say it is a few degrees off. You would have to machine off material to allow it to rotate into position and align at 150 ft-lb. But now the headspace is off. Now the chamber needs to be reamed. If it is a chrome lined chamber/bore, you are SOL. The machinist's time to do all of this makes it impractical. You would be better off buying a complete barrel assembly. If you are a machinist, have access to lathe and other needed tooling, and plenty of time on your hands, fine. I hope you didn't pay much for that barrel. I've also read that the headspace issue on AR's is overblown, and that any stock parts properly tightened down will headspace just fine (this article said not to even worry about go/no-go gauges). As far as your statement about headspace... that is true IF the barrel is a barrel assembly, with the extension already on it. |
Ah that sucks. I wonder why it was missing the extension in the first place? I've never even seen an AR15 barrel with the barrel extension removed. Here's a post from the industry forums by AR15Barrels:
|
|
If you had say 10 (or 50) extensions lying around and plenty of time to try them out to find one that was close enough in thread timing to work, it wouldn't be junk. As a practical matter though, a finished barrel without the extension is useless - with the possible exception of using it with a .22LR conversion kit or the like that doesn't use the locking lugs or the gas port. |
Nope.. the profiles are way different.. And not enough meat to cut the tendon. Fat (been there tried that) McNasty |
