NB444, Eibargun is today known as Lanber. They no longer make SxS's, concentrating instead on U/O's and a couple of models of semi-automatics. Back in the 1970's and early 1980's when they were still making SxS's they were known as economical but soundly built guns. They were exported to Great Britain, Europe and North America with moderate success.
The 10 gauge fowler was popular up until non toxic shot was mandated, and that has proven to be the death of the big gun. Today 10 gauge ammo is virtually exclusively made with steel shot, which is decidedly not compatible with the tightly choked barrels of the Eibargun. Unless you hand load, there is no off - the - shelf compatible ammo available for this gun (except for slugs!).
The gun is a classic Anson & Deeley boxlock, with bolsters on the frame to add strength. Traditional V-springs power the locks. The wood for these guns is never very fancy, rather it is chosen for its tight grain and strength to withstand the recoil. The barrels are well made in the Basque fashion, and usually well regulated. Your example looks to be in reasonably good shape, many suffer scars from the goose pit.
Because of the ammo situation, the value of the 10 bore gun in today's market is very low - about half the price (or less) of a similar 12 gauge. I see them for sale out here for $250 or less.
If you hand load with Nice Shot you will have the most effective goose gun imaginable. Another alternative is to have the chokes opened up to allow the use of steel shot. Because of the nature of the soft soldered barrel ribs the chokes have to be opened quite a bit to ensure safe shooting, and this affects the patterns and effective range. Hand loading is the better route, and you will annoy your hunting partners as you pluck geese out of the sky 10 to 15 yards out of their range.
Federal makes 10 gauge slugs which are compatible with this gun but I have never been able to get them to shoot very accurately, probably because of the chokes. The thing is too heavy to haul around for big game anyway.
In any case, the gun is an interesting addition to any collection and with hand loaded ammo is devastating on big geese.
Sharptail