Okay what can I do with it if I connect to my texan open valve. It let's no air out into gun. Does gun have to be lower than tank .it was used for pcp I guess but need find out what I can do with it.
Like he said the valve is regulated so will only let a regulated amount of air out. If it is paintball stuff it is most often set to around 800-850psi. Although some of the new stuff is a bit higher you will likely not find many set for the 3000 PCP pressure you are after.
You would need this regulator and the special valve that goes with it as regular paintball stuff will not werq.
Looks like you got one of these that has been painted.
Mine is paintball stuff - like they said above. It has a 1200psi regulator on it. By attaching the fill whip with the sliding bleed valve - see green arrow in first photo - I use it to fill my low powered FD XS60C air gun. It works great and get many many refills. But size wise the FD XS60C is about as far away from a Texan as you can get and the bottle may be of little use to you and your Texan.
I have the ninja reg and fill valve listed in the classifieds (4500psi tank with regulated 3000psi output) I took the bottles off to use for something else. If you are interested PM me and I'll put them back together.