Check this out. It's a Walther Talon Magnum, .25, and the spring has been replaced with a Crosman Nitro Piston. If I were to buy a .25 break barrel, I would give this serious consideration. (I currently own a .22 Discovery and a .177 Phantom).
http://www.archerpelletguns.com/Walther-Talon-Magnum-with-Nitro-Piston-p/py-1706-5046.htm