[newxder50]

The more I read the worse I feel about my build...torqued to 35, which seemed just finger-tight and then torqued to next hole for the gas tube, which ended up being 85 foot pounds...I am reading all kinds of crap saying that all hell will break loose if you surpass 80 ft lbs...help a gun-owning, AR- loving brother out so I can sleep...please...is the 85 ft lbs vs. 80 ft lbs that big a deal?????

 

[ajamesp51]

Did you bend or break anything? if not you should be fine.

 

[Davidjlittle]

I would back it off and then try it again. You might get a lower reading. If that is not the deal I would try it with the lower end if there is that much of a difference. I usually get mine around 60 to 75. I try not to go any further and have never seen one blow because of torque specs.

 

[newxder50]

Not that I can tell, everything looks good...this must happen frequently, especially to the guys who "feel" the torque without using a torque wrench right?

 

[Davidjlittle]

yes. When i built my first rifle i had to torque the heck out of it because it was just in between holes. As long as you are using a clam shell upper receiver block you should not twist the upper. that is the biggest thing to watch out for. if your really worried take it to a gunsmith and have him do a once over on it.

 

[HB of CJ]

Am I being set up here? Dunno. Don't care. Yep...85 pounds torque may be too much. Probably. You run the risk of cracking the barrel extension. if this happens, you may not know it until it happens heat cycling the gun...particularly if you shoot fast and the gun gets very hot. If you shoot the gun with a cracked barrel extension, very bad things might happen. May, may not.

Take off the barrel. Do not worry too much about having to go to the next knotch or two to do it correctly. Read my post on dry lube or what lube or grease or not to grease. That post pretty much covers it. Also torque it up dry. Aluminum vs steel. I am sure you can re torque up to about 40-42 pounds and have everything align properly. You can do this. Also fun. HB of CJ (old coot) Passing it forward.

 

[einheit 13]

Am I being set up here? Dunno. Don't care. Yep...85 pounds torque may be too much. Probably. You run the risk of cracking the barrel extension. if this happens, you may not know it until it happens heat cycling the gun...particularly if you shoot fast and the gun gets very hot. If you shoot the gun with a cracked barrel extension, very bad things might happen. May, may not.

Take off the barrel. Do not worry too much about having to go to the next knotch or two to do it correctly. Read my post on dry lube or what lube or grease or not to grease. That post pretty much covers it. Also torque it up dry. Aluminum vs steel. I am sure you can re torque up to about 40-42 pounds and have everything align properly. You can do this. Also fun. HB of CJ (old coot) Passing it forward.

And that is a fact. I just did 2 of them and my largest torque value was 45 to get things to line up.

 

[newxder50]

Here's the thing, I torqued it and took it completely off at least six times, that made no difference, the next hole was still in the same place...let me say CJ that there was no way I was going to take sandpaper to anything on my upper, sorry...so I went with it and ended at about 85 ft lbs...as I said, there felt like little difference between 35 and 85. The majority of people are saying that 85 ft lbs is no problem.

 

[ajamesp51]

The problem would come if you start to bend or crack things. I have felt with some colts, palmetto State, spikes etc that had barrels installed so tight it was like the hand of thor had put them on. The aluminum on the upper would stress before the barrel would. Depending on the wrench you used lets say a two prong version you would start to strip the teeth on the nut.

Now the real question are you reading your torque wrench correctly and or is it calibrated. Jumping from 35 pounds to 85 is a big jump going one tooth. Im not saying it is impossible but it could be a cheap wrench not reading accurately.

If the upper is not cracked or bent, your teeth are not all mangled up and your gas tube is strait and true.
If the barrel index pin did not bend/distort/dig into the upper receiver so you can have a canted front sight.
And she works......... well then it works.

From the factory have have never seen an upper that was sanded to get the timing, unless they were fitted and then sent to anodizing. Not saying people don't do that I just have never seen one.

Some reading
https://dl.dropboxusercontent.com/u/9136061/Gun Stuff/Gun Manuals/usmc_m16a2_manual.pdf
look at 3-41 for a field expedient test to see if you bent anything.

 

[newxder50]

Come to think of it, the barrel nut is aluminum and the upper threads are aluminum as well so it wasn't the harsh mating of steel to aluminum, maybe that helped, but I looked it over carefully with a flashlight and magnification and nothing is off or damaged. I'll let you know this weekend when I fire it. Fingers crossed.

 

[100968]

tighten, reloose, repeat 3-4 times. eventually the holes will line up. repeating this process will give it a better tighter it in the long run

 

[einheit 13]

tighten, reloose, repeat 3-4 times. eventually the holes will line up. repeating this process will give it a better tighter it in the long run

To a point. Te issue would be the coating on the threads. If you work the threads too much, they stand a chance of flattening out. Torque it too much, and they will stretch. When they stretch, the next stop is the threads stripping off the receiver. You aren't gonna hurt the nut.

 

[100968]

I coat mine in grease TW25 before doing anything.

 

[HB of CJ]

Or perhaps put another more polite way, there are many wrong ways and there are some better ways and there may just be a couple of correct ways to properly torque up that pesky AR15 barrel. Read my post about grease or not to grease. No point repeating myself. Gentlemen, stop and just think for a few moments about what you are posting here and what bad things could happen to you.

Steel barrel. Aluminum upper receiver. The correct way to align that barrel nut if it does want to line up, (it never will at first) is to remove the barrel and slightly dress off the end of the upper receiver. Again, read the post in the grease or not to grease thread. This is easy and fun. If one takes the times and has the proper mental attitude on not wanting to blow off your face, then things are fine.

However, if one just wants to not learn and just do it any way, be politely advised that that course of action does lead to the rocks and reefs of potential destruction. Building AR15 riles is fun and easy. Building them correctly is a very good idea. The potential otherwise is not worth the risk. If anybody has any specific questions, please feel free to PEM. HB of CJ (old coot) Just passing it forward.

Forum acting up a bit. Dropping paragraphs and sentences some. The barrel extension is torqued up to around 80-90 pounds. The older barrel extensions had L.H. threads. The barrel gets torqued up to around 40-42 pounds. R.H. threads. Everything needs to go together correctly. We will leave pesky OEM iron site barrel indexing for another time, unless somebody wants to learn more.

 

[100968]

Or perhaps put another more polite way, there are many wrong ways and there are some better ways and there may just be a couple of correct ways to properly torque up that pesky AR15 barrel. Read my post about grease or not to grease. No point repeating myself. Gentlemen, stop and just think for a few moments about what you are posting here and what bad things could happen to you.

Steel barrel. Aluminum upper receiver. The correct way to align that barrel nut if it does want to line up, (it never will at first) is to remove the barrel and slightly dress off the end of the upper receiver. Again, read the post in the grease or not to grease thread. This is easy and fun. If one takes the times and has the proper mental attitude on not wanting to blow off your face, then things are fine.

However, if one just wants to not learn and just do it any way, be politely advised that that course of action does lead to the rocks and reefs of potential destruction. Building AR15 riles is fun and easy. Building them correctly is a very good idea. The potential otherwise is not worth the risk. If anybody has any specific questions, please feel free to PEM. HB of CJ (old coot) Just passing it forward.

Forum acting up a bit. Dropping paragraphs and sentences some. The barrel extension is torqued up to around 80-90 pounds. The older barrel extensions had L.H. threads. The barrel gets torqued up to around 40-42 pounds. R.H. threads. Everything needs to go together correctly. We will leave pesky OEM iron site barrel indexing for another time, unless somebody wants to learn more.

YHM says different. maybe you are right , maybe they are right???? I followed manufactures info on mine. never had an issue.

 

[ace]

When I am building and I notice that the barrel and the upper housing torque will go off of the desired specifications I will do two things depending on the time restraint to build the weapon. The first is to use a shim which is frowned upon with many builders but if you don't want to modify your upper housing it can make the barrel nut torque within your desired specification.
The second way I get the barrel nut to go within specifications is to lap the upper barrel housing, doing this will make the barrel true with your upper housing causing for more of an accurate shot. I like to torque my barrel nut at 50lbs because it is not to tight and not to loose. last trick I use is sometimes the barrel and the upper housing feels loose when I mate them together so I like to use put a film of lock-tight between the barrel and the housing (not the threading on the housing). When the lock-tight dries it turns hard and fills in the gap between the housing and barrel causing both pieces to become more of a singular piece therefor making a more accurate shot.

 

[Mercmar]

Or perhaps put another more polite way, there are many wrong ways and there are some better ways and there may just be a couple of correct ways to properly torque up that pesky AR15 barrel. Read my post about grease or not to grease. No point repeating myself. Gentlemen, stop and just think for a few moments about what you are posting here and what bad things could happen to you.

Steel barrel. Aluminum upper receiver. The correct way to align that barrel nut if it does want to line up, (it never will at first) is to remove the barrel and slightly dress off the end of the upper receiver. Again, read the post in the grease or not to grease thread. This is easy and fun. If one takes the times and has the proper mental attitude on not wanting to blow off your face, then things are fine.

However, if one just wants to not learn and just do it any way, be politely advised that that course of action does lead to the rocks and reefs of potential destruction. Building AR15 riles is fun and easy. Building them correctly is a very good idea. The potential otherwise is not worth the risk. If anybody has any specific questions, please feel free to PEM. HB of CJ (old coot) Just passing it forward.

Forum acting up a bit. Dropping paragraphs and sentences some. The barrel extension is torqued up to around 80-90 pounds. The older barrel extensions had L.H. threads. The barrel gets torqued up to around 40-42 pounds. R.H. threads. Everything needs to go together correctly. We will leave pesky OEM iron site barrel indexing for another time, unless somebody wants to learn more.

Something tells me that you're not a guy who ever took a physics course...right?8)

 

[Davidjlittle]

You could try a different barrel nut. The threads could start in a bad place on the one you have and just wont line up no matter what. Just a suggestion...