Does this gun come with a fill probe?
Yes, the fill adapter is threaded to 1/8" BSPP male
Is this rifle regulated?
Can nitrogen be used to power this gun? many places around here fill nitrogen in hi pressure but not air.
Yes, nitrogen is fine
"The barrel is only the rifled portion of the gun" Maybe I'm not understanding this sentence correctly but what other part(s) of the gun that can be rifled?
Probably referring to the shroud at the end of the barrel.
DOES THIS COME IN A CARBINE 25 CAL. ?
The Carbine's are only available in .22
Is "FAC" the Firearms Certificate one needs in England, or is there a "FAC" for something else? Stupid question, yes, I know, thank you, but I am curious.
Yes, FAC refers to a Firearms Certificate that would be needed in the UK. This denotes that the gun is a high power (over 12 FPE) model.
What is the difference between S500 XTRA FAC and 510 XTRA FAC?
The S500 is single shot.
Is there a true left handed model? With the lever on the left side?
No, there is not.