If the barrel says"2 3/4 inch shells", don't shoot 3 inch magnums. You might get away with it for several hundred shells, or you may crack the stock or forearm with the next shell you fire. If you want a magnum, go buy one, and save the Auto 5 for pheasants quail, and rabbits.
Recommend you have it examined by a gunsmith.
Try the blue book of gun values base on condition
Depends on when it was made. Go to Browning.com and ask.
Try online auctions.
50-450 usd
This is a lightweight 20ga A5 made in 1966. The barrel should be marked for 2 3/4 shells. ***If the barrel is marked for 3" shells then it is not the original barrel. It is not safe to shoot 3" mag shells with the standard receiver.
Unknown.
How do you remove the breech block on a Browning A5 16ga shot gun
No
The .410 Browning A5 is an urban legend. Browninig never produced a .410 A5. No
Browning.
I own a Browning A5, 12ga,Japan made shotgun, ser: 04078. what is it worth?