As stated above the .25 doesn't come with the Slingshot Hammer which makes the gun a whole different animal than the .177 and the .22. I just did a lot of research on these guns and found, at least for me, the .22 was the way to go for sure, followed by the .177.
Anyway, the real reason I'm responding...I just bought a .22 Bantam Hi Lite and was curious about an after market regulator for it. I e-mailed Huma and Brocock to ask if the regulator they are using on the Bantam Sniper will be available for aftermarket purchase. Brocock's people never got back to me but Huma reps did. They told me about 2 weeks ago that aftermarket Huma regulators will be available for all of the Bantams in about a month or month and a half(so 2-3 more weeks). The regulator will screw on between the tank and gun and will have the same gauge as the Sniper but in a slightly different place since it is an aftermarket part. No modifications necessary and although they wouldn't give me a price, should be between $90-$125. I love my Bantam Hi Lite as is but for $125, I'm willing to try the Huma regulator at the advise of some others on the board. Hope this helps.
Have a great Memorial Day weekend and a HUGE THANK YOU to all of you that have served and given for our freedoms and our great country!!!