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10/20/2017 1:01:18 AM
9/22/2017 12:11:25 AM
Posted: 8/9/2005 9:04:50 PM EDT
I would like to find as cheap as possible I only need it once, please let me know thanks
Link Posted: 8/10/2005 3:38:20 AM EDT
Where are you located?
Link Posted: 8/10/2005 6:02:02 AM EDT
Rynich:
Have tools, will travel. Where you at?

Link Posted: 8/10/2005 6:38:26 AM EDT
West of bloomington about 35 miles in Bloomfield, I need to replace a barrel extension. I have a DPMS wrench, I just don't want to bend or scratch up me upper.
Link Posted: 8/10/2005 6:59:46 AM EDT
IYou are more than welcome to use my stuff, but I live on the southside of Indy, so it would be a trip for you.
Link Posted: 8/10/2005 7:08:08 AM EDT
Would it be any problem to have a friend of mine pic it up in the morning and have it back to you later that same day.
Link Posted: 8/10/2005 12:56:03 PM EDT

Originally Posted By rynich:
I need to replace a barrel extension.



What's wrong with it? You do know that will be a bear to replace and re-index, don't you? You'll probably have to re-drill the gas port as well.

If you haven't already found an action block, I've got one as well, and I'm probably the closest.
Link Posted: 8/10/2005 1:01:58 PM EDT
yes, I think it will be an adventure and I'm up to the challenge, M4. If you have one I could borrow that would be great. Any and all pointers you can give me would be much appreciated.
Link Posted: 8/10/2005 1:09:23 PM EDT
What do you mean by drilling out the gas port, isn't that under the gas block. If I do it right why would I need drill out the gas port? Also, no I don't know all the aspects of removing and replacing the Barrel extention.
Link Posted: 8/10/2005 1:26:20 PM EDT
Why do you need to replace the extension? I would think that you would be better off buying a new barrel.
Link Posted: 8/10/2005 1:58:56 PM EDT

Originally Posted By CAR-15:
I would think that you would be better off buying a new barrel.



+1.

The gas port is indexed to the pin in the barrel extension. If you replace the barrel extension, you'd probably have a better chance at winning the lottery than getting the new extension/pin to line up correctly with your original gas port.

Here's how the factory does it:

First the barrel extension is torqued onto the barrel at around 175 ft. lbs. Then it is placed in a jig which indexes TDC using the pin in the barrel extension and then the gas port is drilled.

When you tighten the new barrel extension onto your barrel, who knows where the pin will end up in relation to the gas port. If you remove material from the front of the barrel extension through trial and error and manage to get the pin indexed to the gas port, you'll have changed the headspace. You'll also need a barrel extension wrench, which is probably about the only AR-15 tool that I don't own, and that's due to not having a use for one.

If you need still need to use any tools, contact me and we'll get together.
Link Posted: 8/10/2005 5:06:16 PM EDT
Link Posted: 8/10/2005 6:00:20 PM EDT
Alright now I have to try this, I just can't help myself . Must try the impossible....
M4,
you wouldn't be able to post any pics of this indexing pin would you, I would like to find a barrel but it might be hard to find. I need a CAR-15 barrel in a 1:12 twist, now you see why I'm trying to salvage this one, unless someone has one they want to sell to me. I will still try to replace this extension. If it is made by man I can fix it, unless it is plastic.

Some pics of the proseedure from anyone would be helpful, the BIY section doesn't seem to cover this part of the AR build.
Link Posted: 8/10/2005 6:46:19 PM EDT

Originally Posted By M4Madness:
Here's how the factory does it:



Wow, you really did pay attention in Sully's class, didn't ya?
Link Posted: 8/11/2005 1:27:41 PM EDT
[Last Edit: 8/11/2005 1:28:17 PM EDT by M4Madness]

Originally Posted By rynich:
M4, you wouldn't be able to post any pics of this indexing pin would you?



I've been looking, but have been unsuccessful so far. The indexing pin is just a short, fat pin that sticks up out of the barrel extension at the TDC of the barrel. This pin slides into a slot in the upper receiver to index everything.

Swapping barrel extensions is beyond the capabilities of most do-it-yourselfers. A competent machinist could probably remove material from the breech end of the barrel itself (not the front face of the extension)and recut threads to get the extension's pin to index correctly. Or I guess you could also re-drill the barrel extension in the correct location and relocate the index pin, but you'd have to rig up a jig with the old extension first in order to get the right location.

All in all, it's going to be tough.
Link Posted: 8/11/2005 1:37:32 PM EDT
[Last Edit: 8/11/2005 1:38:16 PM EDT by JimTh]
Index pin visible in these photos from the BIY forum post about assembling your own upper:





Link Posted: 8/11/2005 2:34:24 PM EDT

Originally Posted By JimTh:
Index pin visible in these photos from the BIY forum post about assembling your own upper:

www.kevinholman.com/upper/default_files/image015.jpg

www.kevinholman.com/upper/default_files/image023.jpg




Thanks, Jim. I guess I should have checked there.
Link Posted: 8/11/2005 6:14:20 PM EDT
Rynich, If you haven't picked up M4's block yet and still need one I live in Bloomfield and have one. Just IM me if you need it.
Link Posted: 8/11/2005 8:12:58 PM EDT
Thanks, Jim
I didn't see that when I was over there and I wasn't really looking. I had planned on using the old one for alignment of the new one.
Link Posted: 8/12/2005 1:01:29 PM EDT

Originally Posted By M4Madness:
I guess you could also re-drill the barrel extension in the correct location and relocate the index pin...



After thinking about this today, I've decided that I was wrong on this advice. If you redrill the pin in another spot, your feedramps won't be in the right place. The index pin has to stay where it is.
Link Posted: 8/12/2005 5:58:52 PM EDT
I was trained as an armorer in the army I learned how to break the M16A2 down we were shown how to remove and reinstall the barrel extension but no hands on. It was just for "just in case" training and I think the the instructor just wanted to try it. Doing this project is bringing back some of that info it has been 10 yrs.

PWA4EVER.
Lent me the tools I need thanks guys. The info has been very helpful, it is nice to know that there are so many knowledgable gunowners out there willing to help and this forum is a great resorce.
Link Posted: 8/13/2005 1:45:19 PM EDT
Link Posted: 8/13/2005 8:33:52 PM EDT
I don't think the 175 is problem, if these are machined right the holes and feed ramps should line up. I going to do it because wht do I have to loose, I see I will only learn from having done the process. It si a none functioning barrel as it is now, I can always put it back together or just buy another if I look around. To answer your question yes there is no doubt I'm going to do it, I own guns to work on them that is the fun of it.
Have any of you done this before, when it was shown to me the original extention was put back on so replacing one I don't know about, So, far the input has been great and anymore thoughts on the procedure would be helpful.
rynich pronouced if any one wants to know (ri-nick)
Link Posted: 8/14/2005 6:14:07 AM EDT

Originally Posted By rynich:
Have any of you done this before, when it was shown to me the original extention was put back on so replacing one I don't know about, So, far the input has been great and anymore thoughts on the procedure would be helpful.



Rynick, if you want more info, just start a thread here in the Build It Yourself Forum. Surely someone who has done it before will chime in. Hopefully you'll get it worked out.

Link Posted: 8/15/2005 10:13:33 PM EDT
I put the barrel blocks on the barrel, put it in the vise and went to turn it off and the barrel just kept moving in the blocks. The I took lead brick I have and cut it in half, and made it into a barrel vise setup, the barrel turned in it as well. So, I did what I would do on a FAL, I broke out the dremel and cut down the length of the bad extention until I could just barley see threads. Once ther I took a chisel and wacked it with a 2 lbs sledge, and it cracked along the cut. Before I didd this I made a mark on the barrel shoulder that indexed the key to TDC. Then I measured the depth of the extention from the outside to the barrel face, it was .5041. That should be my headspace depth.

Now once it was cracked it unscrewed quite easly there was some rust on the original threads. I hand tightened on the new extention the hole at the top did not come to the original TDC mark I made. So, now the question I have is, where do I reduce to get the original head space and how much in order to crank on at 175 Ft/lbs to get it right?

I could take some off the front of the barrel extention, but then I would be changing demision on the shoulder of the extention. I could take it off the barrel shoulder, but that would require a lathe, to get it perfect. Does it matter if I change the thinckness of the barrel extention shoulder, and if so what does it change?
If I turn the barrel shouder it shouldn't matter other headspace.

Lastly, what can I do to keep the barrel from rotating as I'm trying to wrench on the new extentioin?
Link Posted: 8/16/2005 5:45:20 AM EDT
[Last Edit: 8/16/2005 5:46:22 AM EDT by claybusting]
To keep the barrel from spinning and with tool you might have at home or can get easy. I would try a good strap wrench. They are made out of rubber. Cheap ones will break but higher ends ones work great. This is all I use to put on Free Float tubes but have use them on so pretty tight stuff. Not sure if the go up to 175lbs but I can check with my snop on man and see what thiers will take.
Link Posted: 8/16/2005 6:38:37 AM EDT
I have a strip wrench but I have not had the sucsess that you have with it. Maybe I need to get a better made one.
Link Posted: 8/16/2005 6:46:35 PM EDT
Link Posted: 8/16/2005 7:19:21 PM EDT
I have a good Craftsman strap wrench and there is NO WAY it would hold the barrel. I'm not sure how you could keep it from spinning.
Link Posted: 8/16/2005 7:23:58 PM EDT
Not saying it will work for 175lbs but The one I got from snap on guy is far better then ones I had from local stores but again it was 100 bucks.
Link Posted: 8/16/2005 7:59:50 PM EDT
Well, man $100.00 that is a lot for a one time deal, I don't think I will spend that much because I would just apply that amount to a new barrel. I will keep it in mind I think the strap wrenches are good for a lot other projects.
Link Posted: 8/16/2005 10:35:15 PM EDT
Link Posted: 8/17/2005 9:41:34 AM EDT
[Last Edit: 8/17/2005 11:48:12 AM EDT by rynich]
That was helpful TWEAK, NOT!

You can shove your 45 series right up your ass, ever hear of GWI. That is when I was trained as run up to our impending doom, I was also sniper trained at that time. I asked the instructor to show me how to remove it, and as you stated yes it is part of the barrel assembly. but if I need to try to fix what I got I wanted to know how to do it all, and he showed me.
I'm also a very strong guy and 150 ft/lb is easy. I crank on FAL barrels with no problem.

What was the other unneeded comment you made.
Baseball bat funny, this just falls in line with me as a person, I think outside the box, I just don't monkey gun assemblies together, that is the same a snap together model. I like doing what others cliam to be impossible because so far in my life I have been able to rub it in thier faces, and I hope this turns out to be the same. I'm sorry that you are so affraid to fail that you find such a project impossible.

If our Forefathers had thought llike you we would not have the M-16 series.

Ok, what I wrote before if any of you saw it was over the top, sorry about that.

I just want constructive comments not defeatists crap.
Link Posted: 8/17/2005 12:58:15 PM EDT

Link Posted: 8/18/2005 3:46:35 AM EDT
Link Posted: 8/18/2005 5:12:38 AM EDT
Tweak,
You started this with your unneeded comments, the flaming was on you and now you want to run away and hide.
If you have changed so many extentions and now you're telling me it is futile, you are full of crap.
I only mentioned the 150ft/lbs because you did, I no longer have books on the subject hence the need for information not critizism.
You asked and I answered about where I got the training, that is not bragging. That is simply answering the question.
If I wanted to look cool for you I would have elaberated on my accomplishments. You on the other hand show yourself as a trolling asshat that didn't even need to comment on this thread.

So, I'm very pleased that you will not be back with your unhelpful and in sulting comments.
Link Posted: 8/18/2005 5:29:26 AM EDT
Hug it out bitches!
Link Posted: 8/18/2005 5:36:33 AM EDT
Hey, Tweak I love you man, there's no need for the haten brother. You did alot in your service, and that is good. As did myself, I had 3 MOS's 1 was 11BP,and later 11MP, 31CP, and last 91BP long story and I'm not going to tell it.

Since you have so much knowledge, then maybe you can tell me and others what where the circumstances that you had to change out so many extentions, and what did you do to fix such a problem?
Lastly, is it such a bad idea to reduce the face of the extention and what is the thread pitch on the barrel under the extention?
Link Posted: 8/18/2005 1:52:26 PM EDT
Tweak, I fail to see what you're so spun up about. He wanted a project, he has one. What's the bfd?


Originally Posted By Tweak:
blah blah words words big red words

Link Posted: 8/18/2005 1:59:52 PM EDT
[Last Edit: 8/18/2005 2:01:37 PM EDT by Tweak]
Link Posted: 8/18/2005 9:02:32 PM EDT
Tweak,

I checked your info and you should be the man on this after working for Armilite.

Seriously can you answer these qeustions, I'm not interested in a pissing match. What I said before still stands though.

Since you have so much knowledge, then maybe you can tell me and others what where the circumstances that you had to change out so many extentions, and what did you do to fix such a problem?

Lastly, is it such a bad idea to reduce the face of the extention?
Link Posted: 8/20/2005 11:30:04 AM EDT
<looks for black & white striped shirt>

I think the point Tweak (and M4M and others) was trying to make was that changing the barrel extension is really hard--hard enough that most armorers aren't even taught how to do it because it's not worth the trouble and you'd be better off buying a new barrel. That being said, since Tweak has changed the bbl extension hundreds of times, there must be reasons to change it and it's obviously possible.

rynich hasn't answered anybody who's asked what's wrong that he needs to change his, so we can't really judge whether he should buy a new barrel or change the extension on this one. He did say something about a 1:12" carbine barrel, which would be hard to find a replacement for. And we know that the barrel was not functional before he started, so he's not going to ruin it trying. Worst case is he has to get a new barrel anyway; best case is he salvages this one.

So, since rynich is committed to trying this no matter who tells him how hard it is, how about we set aside the pissing match over qualifications and move on to helping him get it done?

Problem 1: It's on TIGHT. Applying the proper torque with the wrench doesn't seem to be a problem, but how do you hold the barrel so it doesn't spin?

Problem 2: The new one doesn't index correctly, as expected, so how do you index it? It would seem that you'd need to take a little off of one of the faces, but which one? Does it matter which? [I'm thinking it doesn't matter, so I would take it off the extension since that's replaceable if you screw it up. It would seem to me though, that doing this would affect headspace so you may have to re-ream the chamber, which won't be possible if the barrel is chrome-lined.]
Link Posted: 8/20/2005 9:05:27 PM EDT
Nice post MIKE_L, simply put and to the point.

I don't know what happened to the berrel, but the end result was that someone had ground the feed ramps out. This is a Sendra Carbine that I was wanting to keep original and 1:12 Twist barrels in the 11.5" length are hard to find.

You are right that if I take material of the extention then I have to adjust for barrel face set back, in other words a shorting of the headspace which will make it too tight. The SS extention I have cost me $8.00. So, if I screw it up I will just buy another until I can get it right. It can be done, I recently spoke to a police armorer and he said it can be done its is just going to take some work. He suggested that I remove material from the barrel shoulder instead, thus keeping the headspace the same.

M4 said he could post some pics which I going to try to get them to him.
Link Posted: 8/21/2005 5:54:06 AM EDT
[Last Edit: 8/21/2005 5:55:28 AM EDT by M4Madness]

Originally Posted By rynich:
This is a Sendra Carbine that I was wanting to keep original and 1:12 Twist barrels in the 11.5" length are hard to find.



Sendra never made complete rifles; they only sold lower receivers. That might make it a little easier on your conscience when it comes to swapping parts.


M4 said he could post some pics which I going to try to get them to him.


I hosted them for you and sent you the links via IM. I figured you might want to post them yourself, so that you could add descriptions and such.
Link Posted: 8/22/2005 6:59:33 AM EDT
[Last Edit: 8/22/2005 7:00:18 AM EDT by rynich]
You are coorect about Sendra making the Lowers, but they also sold the CAR-15 kits and that is one thing that got them in trouble. I was also under the impression that they did later sell 2 completed rifles one was called the Commando and the other had a different name I can't remember. If I'm wrong and anyone knows please post the scoop. I was under the impression I had one of the Commando models. Another myth buster for you I was told that the Sendra where colts stamped with the Sendra name, is there any truth to this.

Thanks for the pic info.
Link Posted: 8/22/2005 7:10:55 AM EDT
Ok here are some pics that will show what I started with and what I have done so far.





Link Posted: 8/22/2005 1:40:29 PM EDT
[Last Edit: 8/22/2005 1:42:21 PM EDT by M4Madness]

Originally Posted By rynich:
I was also under the impression that they did later sell 2 completed rifles one was called the Commando and the other had a different name I can't remember. Another myth buster for you I was told that the Sendra where colts stamped with the Sendra name, is there any truth to this.



All I really know about them is that Dick Drasen owned the Sendra Corporation (notice the acronym). There was some sort of BATF investigation regarding Sendra receivers being used to build illeagal SBR's with Nesard (notice the acronym again) parts kits. This was tied in with the Branch Davidians/Waco situation as well in the search warrant. Sendra was also involved in some sort of stolen National Guard parts scheme, but I have no info on that.

According to info here on AR15.com:

Sendra

Post-ban receivers have a circle milled into the side of the magwell. They were originally bead-blasted to a non-glare finish. All others are pre-ban. (This is unverified info…) Also, they used to be NESARD. Rumored to have been owned by Dick Drasen (currently M&A Parts) and produced lowers only out of Barrington, Illinois. No complete guns were sold (again, unverified info).

I guess take it for what it's worth.

As for them being remarked Colt receivers, I figure that is highly doubtful. Prior to the '86 machinegun ban, Bushmaster was converting Sendra receivers to M16 configuration. All of these Sendra conversions have the raised fence around the magazine release. All Colt conversions before the '86 ban are slab-sided SP1's. When Colt switched to the A2 lowers later, they added the sear blocks, which later Sendras also lack. Therefore, we know that Sendra didn't restamp any Colt SP1 lowers prior to '86, and it's a safe bet that they didn't remove the sear blocks from the post '86 Colts and remark them.
Link Posted: 8/22/2005 6:30:22 PM EDT

Originally Posted By rynich:
You are coorect about Sendra making the Lowers, but they also sold the CAR-15 kits and that is one thing that got them in trouble. I was also under the impression that they did later sell 2 completed rifles one was called the Commando and the other had a different name I can't remember. If I'm wrong and anyone knows please post the scoop. I was under the impression I had one of the Commando models. Another myth buster for you I was told that the Sendra where colts stamped with the Sendra name, is there any truth to this.

Thanks for the pic info.



PWA used to call the lower they sold the Commando.
Link Posted: 8/22/2005 10:03:59 PM EDT
I don't know the history that well, mine doesn't have any kind of marking just says Sendra and Serial # and such XM-15 E2 is al that is on the mag well.

Anyway I got the extention timed perfect, but my barrel setback I think is going to be an issue. I'm going to get a couple more extentions later and turn the barrel shoulder down to get the right headspace. I know it is to tight because I had to modify my 22LR conversion to make it fit correctly.
The headspace I know is going to be way to tight, but fot 22LR it should be great. Dry ran some 22LR in it and everything functioned like it should. I will test fire it later this week, I'm going to see about getting another upper at the 1500 this Saturday. I will get a post of the finished rifle up tomorrow.
Link Posted: 8/23/2005 7:14:36 AM EDT

Originally Posted By Tweak:


Pleaase, continue to f*ck up your rifle, as you lack even the most basic understanding of what you are doing this should prove amusing.

M4,

I don't help the hopeless, you gave him great advice at the start which he ignored. There is nothing left to do here.




I am glad to see the moderators here (Tweak) are very polite & are more than willing to help.
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