Expensive look at Cabelas for 1100 barrels, cheaper to buy a new barrel than to have yours treaded for screw in chokes. Having the barrel chopped to 26″ would make sense, just still rememeber you problably will not be able to shoot steel through it.
Due in part the bore constriction is much tighter on older barrel than newer ones. The shells of the old were lower pressure so manufactures made the bore dimensions tigher, to get the speed and velocity they wanted. Now with better shells the barrels have been opened up.
If it was up to me I’d chop 4″ off and just shoot it.