If it is RIFLED, then you're wasting your time shooting buckshot in it.<br>
It's not dangerous, but the twist will spin the wad/shot, and it will scatter badly. Given how few pellets are in buckshot, it makes a totally useless pattern. If there is no wad cup, it's a pain in the ass to clean the lead out of the grooves. And it can lead very badly with shot.<br>
You'd be better off getting a smoothbore barrel for it, preferably one with choke tubes. These can be had with rifle sights, or with a rib, or ribless, in various lengths. The rifle sight models are usually 21" to 23", and there are short ribbed barrels available too. If you're looking for a specific barrel, let me know and I'll check for a part number.