No special reason known. It was given the letter M as the product code when it was introduced in 1968, until 1976 when the letter "M" was replaced by # "137" as the new product code. Occasionally the older Browning guns were given product codes that represented the gun that it was used on such as the letter "S" for Sweet 16's, but a Standard weight 16 ga A5 was the letter "R". The letter M has no special significance other than to identify the model in the serial code indexes.
m=bar 7=1967
You will have to call Browning with the sn.
You will have to call Browning to find out.
The one that starts with "m"
Serial numbers are used by the factory to keep count on total number of firearms made in any given model.
It was made in 1956
The 'M' in the serial number indicates the gun is a BAR sporting rifle, but there was no M57 serialization since the gun was not introduced until 1967. Please check ther serial number.
Your serial number should read 1M 46320,which indicates that you have a Browning auto-5 standard weight shotgun that was made in the year 1961.
Browning.com has sn data under customer service.
You must identify the model number of the gun - the serial number is not sufficient.
The date of production for your Browning BAR is the year 1970.I cannot give a value without a much more detailed description of your rifles overall condition and the amount of original finish remaining on the wood and metal.
You will have to call Browning. The sn you give does not follow standard convention.Your serial number indicates that you have a Browning auto-5 standard weight shotgun that was made in the year 1960.The prefix of zero M to your serial number is the identifying mark that dates your shotgun.It is chambered in 12 gauge.