I have an Ithaca flues 28ga. It is chambered for 2 3/4" shells. The serial number is 395820. I have 2 questions. Did this gun come from the factory with 2 3/4" chambers, or were they lengthened at some point. Since this is one of the later flues, would it be alright to shoot Winchester AA 2 3/4" 1200fps ammo out of it or should I shoot low pressure ammo. Larry Brown said I should post these questions on this board and I would get the answer needed. Thanks in advance for the help.