I have a Browning BAR 30-06 made in 1990 so not one of the newer ones. The normal magazine holds 4 rounds in it and then one in the chamber so the gun holds 5. Does anyone make extended magazines that hold more? I'd think it would be hard since the door thing holds the magazine in or seems to as it snaps to that. I don't know if it's even possible but I just wondered if anyone made them.

I think you answered your own question. It would require a modification to the triggerguard/floorplate assembly to work, and then the standard magazine would no longer work.....

Anything is possible if your local gunsmith is capable. I don't know why you would need THAT many shots but the price for doing that would likely discourage you.

I really don't need anymore as 5 shots is more than enough I just wondered as I thought it would be kind of cool. Not something I'd want to pay a ton on though.

I'd suggest you consider saving up about $4K and finding one of the semi-auto, original pattern Browning Automatic Rifles (of WWII, Korea fame). That'd be much "cooler" than a fine hunting arm with a big magazine jutting out the bottom. Or, for less money, buy yourself an M1A.