Modern 16ga shells are 2 3/4". Older shells were usually 2 1/2" or maybe 2 9/16". You can buy 2 1/2" 16ga shells from Polywad and also RST I believe.
This is a Browning Auto-5 Shotgun, 16 guage made in 1950. It is chambered for 2 3/4" 16 ga shells
This shotgun needs to be examined by a gunsmith.
Brownings made prior to the Second World War could have been chambered in 16 ga, 2-9/16" length. That is no longer a standard SAAMI length and I know of no US companies who load it. You may be able to find a hand loader who can make them for you, you can investigate the European cartridge companies to see if there is a European equivalent, or you can have the gun converted to shoot the longer 2-3/4" shells.
What model????
50-100
Savage Arms
blue an yellow box in good shape full and unfired shells about 30 to 40 bucks Red and black same as above 20 to 30 bucks
50-100 USD or so
Up to 500 uSD
Needs to be evaluated by a GOOD gunsmith.
100.00$
double barrel 16 ga.