It may be different depending on the year and the caliber, but recent catalogs show that the few A-Bolts witha 24" barrel have a rate of twist at 1-10"
The Browning 2007 Product Catalog states that the A-Boltchambered for 25WSSM with a 22" barrel has a 1 in 10" rate of twist.
Browning,s home page should contain this info.
The "rate of twist on rifling" is caliber specific. To give you an answer we would need to know which cartridge the rifle is chambered for.
1 in 14
I think 1 in 14, this is because it is intended for light bullets 50 gr and under. It would be cool if the twist was faster and you could shoot heavier bullets effectively but there would be way tooooooooooo much heat for that little barrel and it just wouldn't last!
It will have to be custom made.
No
Yes
Without a better description, 300-900
No. They would have to completely redesign the bolt, and I cant imagine they would sell well enough to introduce an entirely new bolt face in that model.
If it is a Browning Superposed 12 gauge it was made in 1959.
You will have to contact Browning to find out. If you are referring to the run of Browning model 71's that were made between the mid to late 80's and early 90's, there were a total of 14,000 made. 4,000 Standard Rifles with a 24 inch barrel. 4,000 Standard Carbines with a 20 inch barrel. 3,000 High Grade (Deluxe) Rifles with a 24 inch barrel. 3,000 High Grade (Deluxe) Carbines with a 20 inch barrel.