Try gun shops, gun shows, pawn shops, estate sales, garage sales, Shotgun News, place a want ad, look at for sale ads, egunparts, on line auctions, MidWest Gun Works.
The Winchester Ranger Model 120 typically uses a 12-gauge shotgun barrel. To find a compatible rifled slug barrel, look for a barrel specifically designed for the Winchester 120 series, such as the Winchester 1200 or 1300. Ensure that the barrel is compatible with your shotgun's action and gauge. It's advisable to check with a firearms dealer or the manufacturer for the most accurate options available.
Check the receiver and barrels.
To find the manufacturing date of your Winchester shotgun, check the serial number located on the receiver or barrel. Refer to the Winchester Repeating Arms Company’s records or consult the "Winchester Gun Encyclopedia" for a serial number lookup chart. Additionally, you can contact Winchester customer service or visit their official website for assistance with identifying the production year based on your shotgun's serial number.
download from Winchester home page, will be listed under manuals category.
Try e-gunparts.com, MidWest Gun Works, Shotgun News, gun show, gun shop.
From what I could find your gun is made by Winchester. It should say it on your gun somewhere though.
Depending on the model it can be found on the bottom of the receiver or on the barrel. how to find the year of a belguim browning over and under shotgun by the serial number 53125
Winchester
Library
It's a Belgian gun, the ELG is a Belgian proofmark.
Dixie
Check the receiver and barrel