View Full Version : Over torqued barrel nut... upper receiver or barrel nut ruined?
So my torque wrench is not clicking and I have no idea what I torqued a Geissele barrel nut to a VLTOR upper receiver. When it felt wrong I stopped and backed it off with a breaker bar. So, I don't know if I over torqued it or not, but if I did is the receiver or the barrel nut ruined? Any way to check? I am headed to Home Depot right now to buy a better torque wrench!
Inspect the threads of both, and the face of the barrel nut that contacts the barrel extension for deformation.
I believe your barrel nut is aluminum so either is possibly damaged.
Sounds like a plan ! Thanks!
Barrel nut is pristine and receiver looks fine. Thanks!
You really have to crank on a steel nut to wreck an upper that's 7000 series forged. I only use a torque wrench on fragile systems. Your arm will tell you the correct value after building a few guns.
I agree with MarkM. I would be surprised if you did any damage to either part. Use some moly grease or anti-seize on the threads and tighten and loosen the barrel nut a few times before doing a final torque.
Vltor had a few systems where they welded 6000 series to make a "monolithic" upper/rail system. I used the torque wrench on those to keep it under 40 or whatever their spec was. Other than that, my torque wrench gathers dust now.
Big important part right there that you don't want to overlook.... GREASE that pig before you tighten it down all the way (3x).
As usual, I agree with Todd. There shouldn't be any issue.
Todd- A little while after you left one of the low hire monkeys shattereda old Vltor upper of mine.
Hammer_Man
06-20-23, 15:01
Most 1/2” torque wrenches don’t go any lower than 50 lbs, so you’re not going to get a click on a fastener that only requires 30 - 40 lbs. I used a 3/8” torque wrench with a 3/8” to 1/2” adapter for a long time. Never had any issues with that setup. I had a Snap-On digital torque wrench that could go down to 30 lbs, but that’s overkill for at home gun smithing. I recently picked up a $21.00 1/2” torque wrench at Harbor Freight that goes down to 30 lbs, and that’s what I’ve used on my last build. Lastly, always grease the threads with a moly grease before assembling.
You really have to crank on a steel nut to wreck an upper that's 7000 series forged.
I was curious, and checked https://www.engineersedge.com/torque_table_sae.htm which indicates that one may torque a 1" fine thread 2024-T4 bolt to 166 foot-pounds. The larger 7075-T6 thread can probably take quite a bit more even with shorter than standard thread engagement. I wonder if something else would fail first.
Yes. I’ve seen uppers cracked without damage to the threads from excessive torque.
Yes. I’ve seen uppers cracked without damage to the threads from excessive torque.
Good Grief! Either a defective forging or a complete moron on the barrel nut.
I always use Aeroshell MS33. Back when I started building ARs you could only get MS33 in an industrial size tube so I have enough to build for a battalion :cool:
Very interesting to know that the 7000 series aluminum is more brittle than the 6000. Between the 7000 and 6000 I wonder which would contain a kaboom better? I always thought the 7000 would contain a kaboom better and that it should be the upper of choice on a 300BLK build, but if 7000 is more brittle would it actual increase fragmentation during a kaboom??? Hmmm?
I always thought the 7000 would contain a kaboom better and that it should be the upper of choice on a 300BLK build, but if 7000 is more brittle would it actual increase fragmentation during a kaboom?
A "kaboom" happens when a 300BLK round finds its way into a 5.56 gun. Why would the 300BLK upper be at an increased risk?
Good Grief! Either a defective forging or a complete moron on the barrel nut.
One was clamped not very securely in an old school clamshell, that allowed the receiver to flex and twist. Another was in that stupid fixture that uses the take down pins to hold the upper.
I am a simple gun plumber, not someone who can quote specs and statistics. I say inspect the receiver and barrel nut for damage. If there is no apparent damage, screw the barrel on and shoot the rifle. Unless you are building a rifle to win at Camp Perry, there is not a lot to worry about. If it's accurate and reliable, FIDO (Forget about it and drive on).
One was clamped not very securely in an old school clamshell, that allowed the receiver to flex and twist. Another was in that stupid fixture that uses the take down pins to hold the upper.
While on the subject: I have a Brownells Barrel Extension Torque Tool and I have used this to assemble an upper, meaning the only thing holding the upper receiver was the barrel index pin. How bad is this?
While on the subject: I have a Brownells Barrel Extension Torque Tool and I have used this to assemble an upper, meaning the only thing holding the upper receiver was the barrel index pin. How bad is this?
Pretty bad, but a lot of people get away with it using the Geissele Reaction Rod. The MI-URR is the better tool though.
Pretty bad, but a lot of people get away with it using the Geissele Reaction Rod. The MI-URR is the better tool though.
Yep, spend a couple of more bucks and get the Midwest Industries, it's a good piece of kit.
Pretty bad, but a lot of people get away with it using the Geissele Reaction Rod. The MI-URR is the better tool though.
Yes, I was ignorant of the issue when I bought the Brownells version. No doubt a poor choice for disassembly, but unsure about assembly with a controlled torque of 50 foot-pounds.
Found this from Chad of SOTAR:
I don’t recommend the Geissele Reaction Rod or the Kley Zion Clone. If you use a Torque Wrench, the Reaction Rod type devices are fine for Upper Receiver assembly, but if you plan on tearing down AR Uppers or changing Rails you really don’t want the Reaction Rod. The Reaction Rod is NOT good for trying to remove seized or over torqued Barrel Nuts.
Pretty bad, but a lot of people get away with it using the Geissele Reaction Rod. The MI-URR is the better tool though.
Thank you for your recommendation. Looked it up on the Midway USA website. It's on sale when you add the MI-URR to the "Cart". Price is $90.48. There's an additional 10% off discount code you can apply, GUNSMITHING062023. I jumped on that deal!
Thank you for your recommendation. Looked it up on the Midway USA website. It's on sale when you add the MI-URR to the "Cart". Price is $90.48. There's an additional 10% off discount code you can apply, GUNSMITHING062023. I jumped on that deal!
Awesome! The MI-URR is one of my favorites, along with the 2UniqueLLC barreling spud and the Windham Weaponry barreling jig. Though I still use my set of clamshell upper receiver vise blocks quite a bit.
I was curious, and checked https://www.engineersedge.com/torque_table_sae.htm which indicates that one may torque a 1" fine thread 2024-T4 bolt to 166 foot-pounds. The larger 7075-T6 thread can probably take quite a bit more even with shorter than standard thread engagement. I wonder if something else would fail first.
I wonder WHAT would fail first, not if.
Andy
I wonder WHAT would fail first, not if.
We've certainly seen there are ways (https://www.m4carbine.net/showthread.php?207652-3-Noveske-recievers-scrapped-this-week-Help-please) to fail other parts first. I was thinking even if the receiver were perfectly fixed can you actually deform the threads before the whole thing shears? I could see galling if not lubricated properly, or damage from a poor fitting nut that did not engage the threads properly, but apart from that I wonder if it is even possible.
Hammer_Man
06-26-23, 10:01
+1 for the MI URR. I have the 308 version, and it’s fantastic.
I'd visually inspect the receiver inside and out with a good magnifying glass and light to look for signs of distortion. I'd also perform the oil and wipe test to check for cracks. I'd measure the thread pitch and depth with a good dial caliper. If there are no obvious signs of stress and the specified thread dimensions have not changed significantly, I wouldn't worry about it.
Assemble the rifle and shoot the daylights out of it.
I'd also perform the oil and wipe test to check for cracks.
I am unfamiliar with that. How does it go?
I am unfamiliar with that. How does it go?
You apply a generous amount of oil to the surface of the receiver, or part you are checking, wait about 30 seconds then wipe the area down with a clean cloth. Oil will find its way into a crack and ooze out. You wipe the area a second time, oil oozes out of the crack. It's an old school trick for someone who does not have access to metal inspection equipment you would find in a laboratory or production facility.
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