Nothing
The number before the "V"
Browning.com has sn data under customer service.
You will have to call Browning to find out.The serial number prefix of 6V indicates that you have a Browning auto-5 shotgun that was made in 1966,and the letter V indicates that you have a Magnum model auto-5 shotgun.
It's the model code for a 12 gauge Magnum.
Magnum
Impossible to answer without a detailed description of ALL markings and condition, barrel length, caliber, type of action, finish, wood, box, accessories and papers.
The 5V prefix to a browning serial number indicates that your firearm is a Browning auto-5 Magnum shotgun that was made in the year 1965.
This was used in the serial number prefix with a number to indicate that you have a Browning auto-5 magnum shotgun.the number or numbers before the V indicate the year of manufacture,This was used by browning from 1958-1976.
Information not in the public domain.
The prefix of zero V(0V) indicates that you have a Browning magnum auto-5 shotgun that was made in the year 1960.
1958
Contact Browning.