Gunsmithing Barrel question - What do I have exactly…

[LRshooter6mm]

I picked up this barrel from a prize table and am curious what the markings mean and what barrel I actually have. There was no description with it except Shilen 1:10 .308. Someone smarter than me please shed some light lol here is a couple pics with some dimensions.

 

[Oryx]

Caliber, Twist, Grooves, Material and maker

 

[LRshooter6mm]

Caliber, Twist, Grooves, Material and maker

Can you explain more in-depth? what does the GG, S, XX and stand alone G mean?

 

[Oryx]

That's not a GG ... its a 6G (six groove)
The S is stainless
Can't remember what the XX is but could be some form of match grading?

 

[Oryx]

One of the markings could also be a lot indicator ... I'm not the best resource for this, but someone more knowledgeable will come along or you could likely do some searching on the subject.

 

[45-90]

The 6 G is six groves to go with the 10 twist. S is stainless steel barrel.
XX is a match barrel but not a SM which is a select match barrel...slightly higher quality.
I always get tbe SM when ordering personally... but do not use many of their barrels these days...but the SM's are good barrels.
It should be a pretty good shooter.

 

[LRshooter6mm]

That's not a GG ... its a 6G (six groove)
The S is stainless
Can't remember what the XX is but could be some form of match grading?

Much appreciated