Hansol,
If you look on page two of this site, at my thread entitled "Oak and leather case and rifle modifications" you will see what CAN be done with a good Spanish shotgun as a host gun. The photos aren't the greatest but I think that you'll get the idea. I did have a post here with a lot of photos of the 450 #2 which I built but I guess it's run past the 5-page limit now, as I can't find it any longer.