This might just me being dumb but I have never hear of 2 1/2 inch shells. Could also be one of the many things that I am just too young to understand. Perhaps they are an older thing?If it takes 2 1/2 inch shells 2 3/4 would be dangerous. They will not fully open. And will cause excess pressures. You need to measure the chamber with a depth gauge. Not an unshot 2 3/4 shell . I have an old 16 gauge. It did not state what length shells. It takes 2 1/2. I found out by measuring the chamber.
the Central Arms co was a trade name shotgun made for the Shapleigh hardware co of St Louis by the Cresent Arms company,,Cresent Arms co made alot of doubles and singles for hardware stores and mail order firms from the early 1900's thru the 1930's when the firm was bought by the J Stevens arms co.typically these trade name shotguns will value in the 150 good to around 300 for nice examples,,alot of times i see these tradename shotguns in fair to poor condition because they were USED..and it's very common to find them with cracked stocks .