No
no the 1300 barrel does not have gas ports in it yes the 1300 barrel will fit ,no it does not have the gas ports BUT any competent machine shop or gunsmith can drill out the ports for you.
Any barrel will fit only if you replace the tube also to a conventional 1300 tube.
no
You can.
Try a 1300 barrel
Yes...1200, 1300, 1400, 120 and 140 Butt stocks are interchangeable.
No
No, a magazine extension for a Winchester 1200 shotgun will not work with a Winchester 1300 shotgun. The Winchester 1200 and 1300 have different magazine tube designs and dimensions, so they are not interchangeable.
Yes
The only barrels that will fit the Winchester model 120 are all model 1300 winchester barrels,and most model1200 Winchester barrels.So the answer to your question is No.
Not anymore but I hear you can take a 1300 barrel and have gas ports added and that should work.