Thanks Randall! I decided to go with the Standard in .25, I have plenty of long guns and was interested in the Impact for something shorter. I really don't need the larger bottle because I mainly shoot from my office and the compressor if right there, so refills are not an issue. I also don't have marathon shooting sessions either, so the 480cc bottle should be more than enough. I do want to eventually get a .30 cal barrel, and can always go with the longer 700mm length on it to get more power and efficiency out of the heavier ammo. Most of my airguns have 500mm or shorter barrels, so 600mm is long in my book! The only airgun I have with a 600mm barrel is the Dreamline Classic, and it's really long! The Standard Impact gives me the same barrel length while being over a foot or more shorter.