Hello Chris,
it's .177 with a beech stock. The beech looks really nice. As soon as I saw it I knew I'd be buying it. They had Pro Sports in for £399 but I liked the feel of the TX better.
I was on the verge of buying a Lightning XL, but the stupid sized rail put me off, plus there were too many complaints on here about it as opposed to only one person who said he didn't like the TX.
The AAOC site wasn't working for me earlier, so I'll try again later.

Garry