Molybdenum not a priority?

[csmith]

Is it common for manufacturers to not use molybdenum (or something similar) during installation of the barrel nut on the upper receiver threads? Long story short, I stripped down my AR today and found not even a hint of grease in the threads. The AR is from a brand I'm sure most know of, so if they skipped that step I'm left wondering if most other companies do the same.

[UWone77]

Is it common for manufacturers to not use molybdenum (or something similar) during installation of the barrel nut on the upper receiver threads? Long story short, I stripped down my AR today and found not even a hint of grease in the threads. The AR is from a brand I'm sure most know of, so if they skipped that step I'm left wondering if most other companies do the same.

I'm not surprised some are skipping out on the basics like that. I'm sure some manufacturers were just churning them out as fast as possible. As long as the threads weren't damaged, I'd just re-grease and assemble.

[Eric]

I've found some where it was missing. However, was this on a gun that has been well used and heated up to the point where most of it may have cooked off?

[rob_s]

Most people don't understand how the knockoff companies started making ARs. The concept they used is called "reverse engineering" ( but in most cases saying "engineering" is generous), wherein they took someone else's product apart and either ordered or had made the parts to match to then assemble themselves. This leads to the classic error in reverse engineering, which is that things like torque values, adhesives, lube, staking, materiality, and other immeasurable factors are missed. When you think about it this way it pretty much explains every sub-standard issue with every knockoff AR. This predates any "we're in a hurry to churn out product" by a long shot. If you don't understand the WHY then you really don't understand shit, and most AR makers can't even spell "why". IME, correct use of moly is pretty rare in the knockoff brands.

Moly, the correct moly, doesn't really cook off. However, what matters most is whether or not the barrel is torqued correctly to stay on and then whether or not it releases easily when you remove it with tools. That's what the moly accomplishes; allows correct torque on assembly without causing the dissimilar materials (aluminum for the upper, steel for the nut) to seize so that it can be removed later. Even if it were to somehow "cook off" you would still get the desired effect.

So to the OP, was the barrel nut hard to remove when you applied the wrench and breaker bar, with the upper clamped into a vice using a block, or was it crazy-hard to remove only to discover that there was no apparent moly?

[csmith]

I've found some where it was missing. However, was this on a gun that has been well used and heated up to the point where most of it may have cooked off?

Unfortunately there's no way it's been run that hard just yet.


Moly, the correct moly, doesn't really cook off. However, what matters most is whether or not the barrel is torqued correctly to stay on and then whether or not it releases easily when you remove it with tools. That's what the moly accomplishes; allows correct torque on assembly without causing the dissimilar materials (aluminum for the upper, steel for the nut) to seize so that it can be removed later. Even if it were to somehow "cook off" you would still get the desired effect.

So to the OP, was the barrel nut hard to remove when you applied the wrench and breaker bar, with the upper clamped into a vice using a block, or was it crazy-hard to remove only to discover that there was no apparent moly?

Neither, and that was my other beef. While I can't quantify the amount of force it took to remove the nut, I can say I firmly believe the nut was just tight enough to not come undone.