What kind of shotgun has E L G in a circle on the barrels and the markings U M G on the outside?

The circled ELG is a proofmark indicating manufacture in Belgium. If there is a crown above this mark, it would indicate proof testing after 1893, and if not it would have been earlier. Could the UMG be UMC instead? That could stand for Union Machine Company, a trade name used by Henri Pieper, Herstal, Belgium, 1877-1898.