AR upper receiver help...

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locochinoloco

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So, I've tried to assemble an particular upper and seems like I may have FUBAR it?

The hole where the index pin goes has now deformed and the pin snapped off. I kept the torque to only 40lbs and greased it up so now sure how this happened. The ramp won't align perfect now and the bolt of course won't go into battery. I cleaned up the upper to take pictures.

It's an MAG Tactical upper and they are out of business now so any ideas? Can the upper be salvaged or?

IMG_4689.JPG IMG_4688.JPG
 
As many rifles as I have put together, I got nothing. Never seen that one before. Hang tight, there will be someone along shortly to help.
 
Sorry, Ive got nothing either.
Or only that I've never torqued any...just made sure they were gutentight. :D
And, I've never had any issues.
 
wolfpack65 said:
Sorry, Ive got nothing either.
Or only that I've never torqued any...just made sure they were gutentight. :D
And, I've never had any issues.
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Appears he broke the internet. Helluva first post @locochinoloco

Welcome :D
 
Well that's odd. I would just set a new larger pin and open the hole. Not a huge issue if you have the tools.
 
Looks like maybe the pin was either too short or seated too deeply in the barrel. I can't recall if in a good barrel if the pin is flush with the outer edge of the upper when assembled, but it seems likely. Kind of hard to tell in the picture but it looks like the pin only was indexed against the inner portion of the upper, allowing it to dig it and deform it.

Hard to imagine ....40 ft/lb is not a huge about of torque.
 
@locochinoloco got any pictures of the barrel extension and pin?

I would just go ahead and get a different upper (stripped) like an Anderson and just used the parts from this one.

Like @wolfpack65 i used that German torque and never had an issue with Anderson, SOTA, Aero, and a couple different "off branded".
 
JohnFreeman said:
I can't recall if in a good barrel if the pin is flush with the outer edge of the upper when assembled, but it seems likely.
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This is correct. Should be just flush with the outer edge of the upper. Any higher and it could interrupt the barrel nut I would think.

I think the indexing pin depth was the issue. If the barrel was new I'd be calling or emailing the hell out of who it came from
 
You're supposed to torque the nut, not the barrel. It looks like the barrel was twisted hard in both directions. Did the barrel fit snug in the receiver, or was there a lot of slop? Personally, I would get a new stripped upper. What does the barrel pin look like?
 
That upper is screwed. Go get you a new one.
The index pin that is sheared off I would try to drill it out our go get a new barrel.
 
Step 1 - Take your upper receiver & torque wrench and throw them in the trash. The torque is clearly not working properly or the user doesn't know how to use it.
Step 2 - Buy a new torque wrench, upper receiver and have a gunsmith fix the pin.
Step 3 - Before you attempt to assemble the new parts study up on the subject.

Not trying too condescending, but something went terribly wrong somewhere and you missed it. That kinda damage is about 2 steps past "WTF happened here".
 
Burt Gummer said:
Appears he broke the internet. Helluva first post @locochinoloco
Thanks!! LOL

Welcome :D
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dbracin said:
Adco can replace a broken index pin. The upper is usable as long as it is not cracked anywhere.
https://www.adcofirearms.com/shopservices/shop_qnew2016.cfm?code=Barrel Modification-Repair
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I got the index pin replaced, but was wondering if the upper receiver can be salvaged

backwoodsshooter said:
@locochinoloco got any pictures of the barrel extension and pin?

I would just go ahead and get a different upper (stripped) like an Anderson and just used the parts from this one.

Like @wolfpack65 i used that German torque and never had an issue with Anderson, SOTA, Aero, and a couple different "off branded".
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I got another upper receiver, but just hate to toss this one away.... :|

bigfutz said:
You're supposed to torque the nut, not the barrel. It looks like the barrel was twisted hard in both directions. Did the barrel fit snug in the receiver, or was there a lot of slop? Personally, I would get a new stripped upper. What does the barrel pin look like?
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I used the Geissele reaction rod... so I'm assuming that I can only torque the nut? :)

muskrat said:
Step 1 - Take your upper receiver & torque wrench and throw them in the trash. The torque is clearly not working properly or the user doesn't know how to use it.
Step 2 - Buy a new torque wrench, upper receiver and have a gunsmith fix the pin.
Step 3 - Before you attempt to assemble the new parts study up on the subject.

Not trying too condescending, but something went terribly wrong somewhere and you missed it. That kinda damage is about 2 steps past "WTF happened here".
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It's all good... LOL .. I don't take it personal.... maybe it's this MAG Tactical upper receiver?

Wahoo95 said:
Scrap that upper. Bring the parts over and I'll help with getting the new parts assembled.

Sent from my SM-N910V using Tapatalk
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Thanks for the offer!
 
I have never used a reaction rod, but based on the design it shouldn't cause this damage. From the damage it's clear that there was a lot of torque between the barrel and upper, do you know what caused this?
 
locochinoloco said:
Do you speak from experience? Did this happen to you also?
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I use a clam shell style and have had no problems. Before I bought, I researched and found more problems associated with the reaction rod verses other types. So, just my experience and my opinion. [emoji52]
 
JimB said:
I have never used a reaction rod, but based on the design it shouldn't cause this damage. From the damage it's clear that there was a lot of torque between the barrel and upper, do you know what caused this?
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I will take some pictures when the barrel come back from ODIN with the new index pin to show where they touch.

dbracin said:
I use a clam shell style and have had no problems. Before I bought, I researched and found more problems associated with the reaction rod verses other types. So, just my experience and my opinion. [emoji52]
Click to expand...

My apologizes if I came off a bit strong, I thought you had the same issue and/or experience and we can compare notes. But thanks for your two cents, because every bit helps. This is 2nd that I've messed up out of 5 and I'm trying to figure out is it me or the rod. LOL. But I did swap the barrel on this upper multiple times.
 
Johnny said:
I have seen similar when using an upper clamp instead of a barrel vise.
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I would think the opposite based on mechanics but zero experience. Seems you would want to hold the piece (receiver) you are torquing against, not the floating piece getting sandwiched in (barrel). Along the same line of logic, I would never think to use a receiver clamp when torquing a muzzle device.
 
bigfutz said:
I would think the opposite based on mechanics but zero experience. Seems you would want to hold the piece (receiver) you are torquing against, not the floating piece getting sandwiched in (barrel). Along the same line of logic, I would never think to use a receiver clamp when torquing a muzzle device.
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I don't believe that the barrel nut bottoms out against the receiver, it bottoms out against the barrel to ensure that the barrel is tight. Obviously there are 3 parts and a bunch of friction, but either the reaction rod or upper vice block should work if used properly. If this is a common problem it'd be easy to produce a block that holds the upper and the barrel in alignment while the barrel nut is being tightened or loosened.

It's also possible that the upper and/or the barrel were goobered before the current effort, making all our guesses worthless.
 
So... I just wanted to update the thread. I bought it to a buddy of mines and it seems like the play on the reaction rod in the chamber is what cause the problem.

He had the receiver clam and that fixed it....

Gonna contact Geissele and see what's up.

Thanks everyone!
 
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