Is an old remington 1880something 10gauge SxS worth much and also would it be any good to hunt with or is it just more of a gun to hang above a fireplace?

Have it checked by a smith before firing it! It may have twisted steel barrels or a non-standard chamber. It may also not be suited to today's 10 gauge loadings. It may be a fine shotgun that should become a valued wallhanger.

What you have is probably a Model 1889. Like OEH said get it checked out, by a SHOTGUN smith that knows about this type of shotgun. If it is in sound condition, it is safe to shoot with the proper ammo. That said, handloading is the only way to get safe LOW PRESSURE 2 7/8" ammo to feed it. I shoot my Parker Bro. 10ga (1914) w/ damascus barrels. The bottom grade (I) has fluid steel barrels the higher grades usually have high grade Damascus barrels.

Sherman Bell did an article in Double Gun Journal on smokeless and BP loads for the 2 7/8" 10ga. These are all with pressure test data, so it is not just theoritical.

If you are scared of it, just send it to me, as a "need" a hammer 10ga.

Hog Killer