Moisture in upper after range session

[odie64]

I noticed some moisture in my upper receiver at the top after my initial range session with my PSA PA10 Build. The rifle functioned flawlessly and I was using Sellier & Bellot  .308 (147gr??) ammo. It's hard to tell but it looks like it may be coming from the gas tube. The rifle has  PSA (fn) 14.7 barrel with a pinned and welded SilencerCo 7.62 specwar muzzle brake. I have other AR Platform rifles in 5.56, 9mm and 300 blackout and never noted this on any of those calibers. This is my first 308AR rifle, is this common or signs of something wrong?

[mineralman55]

Maybe PSA built a water-cooled version? 

 

Sorry, couldn't resist. It's probably nothing.

[odie64]

Well you know it IS a Gen 2.  I didn't have a function issue and it did not seem to be a safety issue. I just posted to see if I was the only one that had this

[98Z5V]

Lube.  Whatever lube you use - the heat from firing is separating the lube components. 

[survivalshop]

26 minutes ago, 98Z5V said:

Lube.  Whatever lube you use - the heat from firing is separating the lube components. 

  Or if the rifle was stored in an air conditioned space ( home , Auto ) before the range ,its possible  it could be condensation formed when brought out into the heat . You need to first actually determine what it is , water ( moisture ) or separation of the Lubricant as described above .

[98Z5V]

It's completely atmospheric, as well - it may be the same for the other weapons platforms fired, but vastly different weather conditions at the time of their firing...

[odie64]

I did use some grease to lube the threads on the barrel nut when I assembled the upper. It does seem to have an oily property to it. If that is the case I suspect after a short time it will dissipate completely.