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Posted: 11/12/2015 1:59:17 PM EST
So I was taking a barrel off of a Bushmaster AR-15 in order to replace the factory handguard with a free floating handguard.

I put the upper in the vise on a DPMS Claw vise block. I know many here do not like these but I have had no problems with them for what I use them for. I set my torque wrench for 60 ft/lbs and eased into it.* Click! Well, it's gonna take more torque so I reached for the Brownell's "reaction rod" and mounted my armorer's wrench in the vise. Turned the dial to 80 ft/lbs and give it another go. Click! I leaned into it a little more and finally got something to move when I noticed the M4 feedramps no longer lined up with the ramps in the upper. Uh oh!

After plenty of penetrating oil and heat I finally got the barrel nut off. Funny thing is, I was able to get it off with 60 ft/lbs of torque and while using the DPMS Claw block.

I was worried that I had damaged the upper. However, all I did was break the index pin. Now to get that out, which is the purpose of this thread.

(* I did a little research and now understand that removal torque can be much higher than assembly torque.)

After searching the net and finding some people getting broken index pins out easy and and some people having to send them out and pay $50 to have them removed. Having more tools and time than money I decided to give it a go.



Here is the index pin broken off in the barrel.


I used a center punch to mark the center of the index pin for drilling. You can't see it in the photo but the center punch easily dented the index pin. I guess the center of the pin is much softer than the outsides of the pin.


This is what the index pin looked like after I drilled into it with a 1/16" drill bit.


I was careful not to drill too deep. I knew I had drilled all the way through the index pin when I saw some of the penetrant I had previously used creep up through the hole.


Next I stepped up to a 5/64" bit. I was careful not to drip all the way through, and I used the 1/16" as a depth reference.


The final bit I used was a 3/32" bit.


I used a 7/64" screw extractor and was able to get the index pin the lift up enough to grab it with pliers.


There is the shell of the index pin.

Link Posted: 11/12/2015 2:04:03 PM EST
A few more pictures.



I was really surprised but there was no real damage to speak on the upper.




I tapped the new index pin back in with a little Delrin punch. I keep index pins in stock and I get them from Anderson.




The barrel slipped right back into the upper and there was only a marginal increase in play between the index pin and the slot in the upper.
Link Posted: 11/12/2015 2:40:15 PM EST
[Last Edit: 11/12/2015 2:55:19 PM EST by 556Cliff]
Score another one for the Reaction Rod style tools!

I would not be surprised if that upper gives you problems with iron sight alignment now, unless that barrel just has a gas block.

The index pin notch took a lot of pressure judging by the distorted threads on left side of the notch.
Link Posted: 11/12/2015 2:56:32 PM EST
Originally Posted By jonblack:
So I was taking a barrel off of a Bushmaster AR-15 in order to replace the factory handguard with a free floating handguard.

I put the upper in the vise on a DPMS Claw vise block. I know many here do not like these but I have had no problems with them for what I use them for. I set my torque wrench for 60 ft/lbs and eased into it.* Click! Well, it's gonna take more torque so I reached for the Brownell's "reaction rod" and mounted my armorer's wrench in the vise. Turned the dial to 80 ft/lbs and give it another go. Click! I leaned into it a little more and finally got something to move when I noticed the M4 feedramps no longer lined up with the ramps in the upper. Uh oh!

After plenty of penetrating oil and heat I finally got the barrel nut off. Funny thing is, I was able to get it off with 60 ft/lbs of torque and while using the DPMS Claw block.

I was worried that I had damaged the upper. However, all I did was break the index pin. Now to get that out, which is the purpose of this thread.

(* I did a little research and now understand that removal torque can be much higher than assembly torque.)

After searching the net and finding some people getting broken index pins out easy and and some people having to send them out and pay $50 to have them removed. Having more tools and time than money I decided to give it a go.


http://www.melitafain.com/ar15/index-pin-001.jpg
Here is the index pin broken off in the barrel.

http://www.melitafain.com/ar15/index-pin-002.jpg
I used a center punch to mark the center of the index pin for drilling. You can't see it in the photo but the center punch easily dented the index pin. I guess the center of the pin is much softer than the outsides of the pin.

http://www.melitafain.com/ar15/index-pin-004.jpg
This is what the index pin looked like after I drilled into it with a 1/16" drill bit.

http://www.melitafain.com/ar15/index-pin-005.jpg
I was careful not to drill too deep. I knew I had drilled all the way through the index pin when I saw some of the penetrant I had previously used creep up through the hole.

http://www.melitafain.com/ar15/index-pin-006.jpg
Next I stepped up to a 5/64" bit. I was careful not to drip all the way through, and I used the 1/16" as a depth reference.

http://www.melitafain.com/ar15/index-pin-007.jpg
The final bit I used was a 3/32" bit.

http://www.melitafain.com/ar15/index-pin-009.jpg
I used a 7/64" screw extractor and was able to get the index pin the lift up enough to grab it with pliers.

http://www.melitafain.com/ar15/index-pin-010.jpg
There is the shell of the index pin.

View Quote

Just a note, you shouldn't use a torque wrench to loosen things.....
Link Posted: 11/12/2015 2:57:04 PM EST
[Last Edit: 11/12/2015 3:08:53 PM EST by jonblack]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By 556Cliff:
I would not be surprised if that upper gives you problems with iron sight alignment now, unless that barrel just has a gas block.

The index pin notch took a lot of pressure judging by the distorted threads on left side of the notch.
View Quote

The gun has a gas block, not a front sight. However there was very little play, not much more than the acceptable play on any other upper/barrel assembly.


Link Posted: 11/12/2015 2:57:50 PM EST
[Last Edit: 11/12/2015 3:11:45 PM EST by jonblack]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By lysanderxiii:
Just a note, you shouldn't use a torque wrench to loosen things.....
View Quote

Please don't quote the whole post, or the pictures. It looks messy in a technical forum. Would you mind editing your post to remove all the quoted text and photo links?
Link Posted: 11/12/2015 3:01:08 PM EST
[Last Edit: 11/12/2015 3:08:21 PM EST by jonblack]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By lysanderxiii:
Just a note, you shouldn't use a torque wrench to loosen things.....
View Quote

I understand that loosening torque can be much higher than assembly torque. However, I use the torque wrench as a guide to keep me from overloading my vise block. My understanding is that you can exceed the capability of the torque wrench and mess up the calibration, but I don't think that would be the case in this situation since I didn't keep torquing until the barrel nut broke free.
Link Posted: 11/12/2015 3:03:34 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By 556Cliff:
The index pin notch took a lot of pressure judging by the distorted threads on left side of the notch.
View Quote

I don't see any distorted threads and the photos make it look a good bit worse than it is.
Link Posted: 11/12/2015 3:09:39 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By jonblack:

I don't see any distorted threads and the photos make it look a good bit worse than it is.
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By jonblack:
Originally Posted By 556Cliff:
The index pin notch took a lot of pressure judging by the distorted threads on left side of the notch.

I don't see any distorted threads and the photos make it look a good bit worse than it is.


Looking at it in person might make a difference but the pics definitely make it look bad... On the verge of cracking bad.
Link Posted: 11/12/2015 3:14:23 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By 556Cliff:
Looking at it in person might make a difference but the pics definitely make it look bad... On the verge of cracking bad.
View Quote

In person it did not look anywhere near close to cracking. In fact looking from the top I didn't see any distortion. Only from the bottom could you see anything. I had to look pretty close to see the indentation with the naked eye.
Link Posted: 11/12/2015 3:16:29 PM EST
I'm wondering if you are thinking the "smear" from the index pin removing the anodizing inside the upper is damage. I could barely feel the "smear" with my fingernail.
Link Posted: 11/12/2015 3:50:39 PM EST
[Last Edit: 11/12/2015 4:00:51 PM EST by 556Cliff]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By jonblack:
I'm wondering if you are thinking the "smear" from the index pin removing the anodizing inside the upper is damage. I could barely feel the "smear" with my fingernail.
View Quote


That "smear" is a bulge caused by the index pin, when the index pin sheared it took the anodizing off of the bulge making it look like a smear.

The bulge was likely more pronounced before the sheared index pin gave it a haircut.

In both the 1st and 3rd picture of the upper I can see distorted threads on the left side of the notch. I'm not saying the upper won't work, I'm just trying to point out that the Reaction Rod style tools suck, especially the Brownells version when used how the instructions say to use it.
Link Posted: 11/12/2015 4:08:12 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By 556Cliff:
In both the 1st and 3rd picture of the upper I can see distorted threads on the left side of the notch. I'm not saying the upper won't work, I'm just trying to point out that the Reaction Rod style tools suck, especially the Brownells version when used how the instructions say to use it.
View Quote

Looking at the photos I don't see what you are calling damage on the threads. Also, the damage (if any) would have occurred on the right side, which is the side the index pin shear off on.

Thank you for clarifying your position regarding whether the upper will work. The upper will work just fine. Again, any "damage" is negligible and in no way affects the barrel nut's ability to hold the barrel in place.

Link Posted: 11/12/2015 4:24:39 PM EST
[Last Edit: 11/12/2015 5:17:20 PM EST by 556Cliff]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By jonblack:

Looking at the photos I don't see what you are calling damage on the threads. Also, the damage (if any) would have occurred on the right side, which is the side the index pin shear off on.

Thank you for clarifying your position regarding whether the upper will work. The upper will work just fine. Again, any "damage" is negligible and in no way affects the barrel nut's ability to hold the barrel in place.

View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By jonblack:
Originally Posted By 556Cliff:
In both the 1st and 3rd picture of the upper I can see distorted threads on the left side of the notch. I'm not saying the upper won't work, I'm just trying to point out that the Reaction Rod style tools suck, especially the Brownells version when used how the instructions say to use it.

Looking at the photos I don't see what you are calling damage on the threads. Also, the damage (if any) would have occurred on the right side, which is the side the index pin shear off on.

Thank you for clarifying your position regarding whether the upper will work. The upper will work just fine. Again, any "damage" is negligible and in no way affects the barrel nut's ability to hold the barrel in place.



I don't mean that the threads are mangled, chipped or stripped, they just looked outwardly distorted toward the face of the upper. In spite of this though the upper should hold a barrel just fine.

Now, If the index pin sheared while using the DPMS Claw block any damage to the upper would be on the right but the fact that the damage is on the left is a result of the Brownells Reaction Rod. This is from a loosening perspective, it would be opposite if this happened while tightening.


Edit: I saw your last post before you edited it, yes this is a matter of perspective. I am referring to left and right as in the upper receiver's actual left and right side. Not how it's facing us in the pictures.
Link Posted: 11/12/2015 5:03:08 PM EST
[Last Edit: 11/12/2015 5:07:20 PM EST by jonblack]
I edited this to try to keep the tread on track.
Link Posted: 11/12/2015 5:06:43 PM EST
With all due respect, can we keep this thread on track of the original intent? As stated in bold in the unedited OP, the purpose of this thread is to show how I got the sheared index pin out. I wanted to make this  thread to help others who may be in the same situation I was in.
Link Posted: 11/12/2015 5:18:26 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By jonblack:
With all due respect, can we keep this thread on track of the original intent? As stated in bold in the unedited OP, the purpose of this thread is to show how I got the sheared index pin out. I wanted to make this  thread to help others who may be in the same situation I was in.
View Quote


No problem, see the edit in my last post.
Link Posted: 11/12/2015 5:21:11 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By 556Cliff:
No problem, see the edit in my last post.
View Quote

Thanks brother. And, in a matter of full disclosure, I happen to agree with you regarding the reaction rod type tools. It just happens to be the tool that I used on this upper, and admittedly, is the cause of the broken index pin.
Link Posted: 11/12/2015 8:23:42 PM EST
We've heard it over and over again. Unfortunately. Reaction rods are not the best tool. You hold the threaded receiver and wrench the barrel nut. Holding the extension and turning the nut is not the right way. You did a good fix. I hope it shoots well for you.
Link Posted: 11/15/2015 1:13:28 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By wools10:
We've heard it over and over again. Unfortunately. Reaction rods are not the best tool. You hold the threaded receiver and wrench the barrel nut. Holding the extension and turning the nut is not the right way. You did a good fix. I hope it shoots well for you.
View Quote


People will still argue that it's fine and we will always have these threads.

Posted Via AR15.Com Mobile
Link Posted: 11/18/2015 11:24:58 AM EST
I tapped the new index pin back in with a little Delrin punch. I keep index pins in stock and I get them from Anderson.

Nice to know that.
I wanted to change hand guards but had a barrel nut that was hell to get lose. Upon closer inspection i saw the "competent highly skilled gunsmith" Who originally assembled the upper used RED LOCTITE!!.
After finally removing the bbl i see why this hack used LT. Turns out he sheared the pin when installing. After getting the shit removed and checking alignment of bbl pin to gas port, i decided to make my own. Thankfully having a lathe pays off, eventually. Turned some small stock down and was able to get the bbl back in service.  Now all i need is a tap for the buffer tube hole as that was fuked too.
Link Posted: 11/18/2015 6:31:43 PM EST

Originally Posted By jonblack:


So I was taking a barrel off of a Bushmaster AR-15 in order to replace the factory handguard with a free floating handguard.



I put the upper in the vise on a DPMS Claw vise block. I know many here do not like these but I have had no problems with them for what I use them for. I set my torque wrench for 60 ft/lbs and eased into it.* Click! Well, it's gonna take more torque so I reached for the Brownell's "reaction rod" and mounted my armorer's wrench in the vise. Turned the dial to 80 ft/lbs and give it another go. Click! I leaned into it a little more and finally got something to move when I noticed the M4 feedramps no longer lined up with the ramps in the upper. Uh oh!



After plenty of penetrating oil and heat I finally got the barrel nut off. Funny thing is, I was able to get it off with 60 ft/lbs of torque and while using the DPMS Claw block.



I was worried that I had damaged the upper. However, all I did was break the index pin. Now to get that out, which is the purpose of this thread.



(* I did a little research and now understand that removal torque can be much higher than assembly torque.)



After searching the net and finding some people getting broken index pins out easy and and some people having to send them out and pay $50 to have them removed. Having more tools and time than money I decided to give it a go.





http://www.melitafain.com/ar15/index-pin-001.jpg

Here is the index pin broken off in the barrel.



http://www.melitafain.com/ar15/index-pin-002.jpg

I used a center punch to mark the center of the index pin for drilling. You can't see it in the photo but the center punch easily dented the index pin. I guess the center of the pin is much softer than the outsides of the pin.



http://www.melitafain.com/ar15/index-pin-004.jpg

This is what the index pin looked like after I drilled into it with a 1/16" drill bit.



http://www.melitafain.com/ar15/index-pin-005.jpg

I was careful not to drill too deep. I knew I had drilled all the way through the index pin when I saw some of the penetrant I had previously used creep up through the hole.



http://www.melitafain.com/ar15/index-pin-006.jpg

Next I stepped up to a 5/64" bit. I was careful not to drip all the way through, and I used the 1/16" as a depth reference.



http://www.melitafain.com/ar15/index-pin-007.jpg

The final bit I used was a 3/32" bit.



http://www.melitafain.com/ar15/index-pin-009.jpg

I used a 7/64" screw extractor and was able to get the index pin the lift up enough to grab it with pliers.



http://www.melitafain.com/ar15/index-pin-010.jpg

There is the shell of the index pin.



View Quote
Great post. Thanks.

 
Link Posted: 11/18/2015 9:32:05 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By therealdonjohnson:
Great post. Thanks.  
View Quote

Thank you and I hope it helps someone in the event they ever break an index pin.

On a side note would you do me a favor and edit your post so it doesn't quote my entire post? It just make a technical thread hard to read. Thanks in advance.
Link Posted: 11/18/2015 10:28:17 PM EST
So what causes the pin to shear off?
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