I think you're going to find they're all about the same length. Why is the barrel too long? You're not planning on trying to hold it up to the side of your head are you, and trying to fire it that way???? Most people who use a shotgun for ctb place the stuck (butt) end of the gun on the floor, sit on the edge of a chair, and then stick the barrel into their mouth at a slight upward angle. Doing it this way changes the geometry of the person to the gun and makes the trigger much more "reachable".
It's not my intention to condemn or condescend. Your English seems very good. My only point is that it's much better for you just to peruse gun websites, perhaps in your locale, until you find one that meets your needs. Again, barrel lenght isn't going to vary by that much. There are federal laws (I don't know about that where you are from, but in the US there are) that govern that aspect. Also, a certain barrel length is necessary to "conform" the projectile(s) in the barrel. Even in the US, "sawed-off" shotguns are illegal. Now, that's mostly because doing so makes them easier to conceal (for robberies and such), but a sawed-off shotgun also has more "scatter" of projectiles and reduced accuracy when it's fired because the barrel has been shortened. I guess for ctb purposes, it really wouldn't matter, but you're not going to find one - you'd have to do "it" yourself with a hacksaw.
Are we good?
