I have a Bonehill Interchangeable 12 ga bar action sielock with 30.5" steel barrels & looks very similar to the one pictured herein. It's a 2 3/4" chamber & reproofed. My hammers seem identical to yours as well as the engraving. It was once owned by a well-known collector and shotgun shooting author. Mine is in excellent condition for age and I use it for dove & quail hunting. I have shot many shells around 10,000 lbs pressure & 1 oz loads with no problems. It patterns beautifully and is a joy to use. It gets a lot of attention in the field. I think yours would be worth saving.
