My 2 Cents
This is an old post but I inherited my 59 from my grandfather who used it extensively. It actually had 3 barrel options. one is the 26" IC barrel for the different choke options, I have all 3. Also, there were 2 other barrels, 29.5" Full choke, and 27.5" Mod. Only one I am missing is the 29.5" Full. I agree with low velocity load <1200 FPS and no steel for this barrel type. All in all though, this gun has ahead of it time from 1960-65. I remember going good and duck hunting with my grandfather and he used it a lot. Given that, the barrels show no wear so I assume he took good care of it. I did have to replace the ejector as it was worn and not grabbing the shells, now it is fine. Part are available at time at Numrich.