Jeff, the closest place to you that I know you could likely get some 2 1/2" 16 ga would be Fieldsport in TC, likely about $8 box. That said i have shot alot of "standard" 2 3/4" field loads out of a 16 flues with short chambers with no probs to date but knowing there is danger in cracking the frame, you dont want to shoot those high velocity out of it, save them for a modern gun.