Browning.com has manuals you can download for free.
Best left to a gunsmith.
Remove the end cap.
Best to ask a gunsmith for help.
Yes.
Remove the rubber cover and plug lead from spark plug. Using a bike plug spanner [cheap at your favourite auto supermart] remove plug.
A feeler gauge is actually a set of very fine strips of steel used to measure small gaps such as plug gap of an auto plug, or gaps in bearing surfaces.
Remove the tank and drain it unless it has a drain plug on the bottom of the tank.
Yes, they did. My Dad owned one and it was an automatic 12 gauge capable of 5 shotgun if the plug was removed.
Get a "Spark Plug Boot Removal Tool", available at any reputable Auto Parts Store.....
There are pliers available that do just that. Check with your local auto parts store.
remove drain plug and fill plug uses dexron gm auto trans fluid