The two guns are similar although the major is larger,has different sights, a longer cylinder and barrel and an adjustable trigger. Early versions had a small stock screw in front of the trigger guard and later ones the large bolt through the stock into the trigger block (5/16 BSF by the way). The front ones are 7/32 Bsf and you will have to get them from Nibbs if you need them unless somebody could make a batch up? The barrel and the trigger housing are interchangable on the guns but if you fitted the major barrel to a cadet you would need to retain the cadet cocking arm.
Remove stock screws and remove action from stock. remove cocking arm pin and cocking arm. Knock out barrel pivot arm remove barrel and watch out for plunger and spring which are just pushed into the cylinder and not retained. If you have to change the breech washer its a bugger to fit a new leather one (your on your own with that) but in AGW the bloke used a bit of plastic with 12mm OD and 8MM ID and habd finished it. I have heard of people using two "O" rings. If its a Major you can undo sear adjuster screw a bit then knock out sear pin and remove sear spring and sear. GO TO NEXT POST