I am aware of only the following calibers in the B78: 22 250; 6mm Rem, 7mm Rem Mag; 30 06 and 45 70.
Yes, the B78 rifle was produced in .280 Remington caliber. The B78 is a single-shot rifle manufactured by Browning in the late 1970s and early 1980s, and it was available in several calibers, including .280 Remington. This caliber was among the options offered to cater to various hunting needs.
It happens. Does not add any real value.
Between 1973-75
The Browning B78 rifle's date of manufacture can be determined using its serial number. For the B78 series, the first two digits of the serial number typically represent the year of production. In this case, with the serial number 70792W57, the "57" indicates that the rifle was manufactured in 1977.
You will need to include a serial number to have your question answered.
W73 to 76 and then to current two letter code
7mm Magnum and 300 Winchester Magnum
No. The B78 wasn't introduced until 1973 and discontinued in 1982 You need to contact Browning. You can get it lettered for 39.50 USD
Browning.com has a sn function under customer service
With a flat screwdriver , their are 4 positions, eject straight out the rear , to the left or to the right, and a stop or catch position.
No
The B78's were made for Browning by Miroku of Japan from 1973 to 1982 and the values vary a bit. A moderately used 78 in a popular caliber will run from $800 to $1500. Their popularity is apparently on the way back and Winchester has started making a Model 1885 which is basically the same gun with less flashy wood and not many chamberings. Browning had made an 1885 Model back in the 90's for a few years. I purchased a mint 6mm B-78 two years ago for $850 and thought it one hell of a deal.