Why does the Dan Wesson 6" Pellet Revolver have only a 2.5" inner barrel? Is there any similar replica revolver with a full length rifled barrel?

So I've been shopping for a pellet revolver for awhile. Looking for one that looks and behaves like the real thing as much as possible, while also being as accurate as possible. Preferably in a roughly 6" size.

I really thought I found the winner with this one.
https://www.airgundepot.com/dan-wesson-6-revolver-silver.html

It looks absolutely beautiful. I really like everything about the look. And it operates like the real thing. Uses pellets and a rifled barrel for accuracy. And has adjustable sights for windage and elevation. It seemed perfect.

But then I saw one detail that seems like a deal-breaker. It says "Rifled 2.5in barrel w/ 6" outer barrel"

So the whole 6" barrel is just a fuax and this is no different than a 2.5" other than longer distance between sights? Why would they make it like this? Is there really any reason that I'm unaware of why they didn't just make a full 6" rifled barrel other than maybe a tiny increase in cost? It seems like this is such a shortcut that is sacrificing the accuracy it could have had that would have made it a full package. (But maybe there are reasons I am unaware of and don't know what I'm talking about.)

Anyways, I tried looking for any other similar revolver that has all these features plus a legitimate full length rifled barrel, and so far haven't found anything. Anyone know of any?