What is the Choke on this Auto 5?

[Chumango]

I have the opportunity to purchase an FN made Browning Auto 5, light 12, 1965 vintage, as far as I can tell. I cannot see any marks on the barrel to indicate the choke, at least that I recognize as such. Apart from measuring with a caliper, which I don't have, is there a way to determine the choke? There is no paperwork with this one. The widow of the son who inherited it is selling it.

The wood is a little dinged up, but the steel is in great shape with virtually no wear to the bluing. The bore is smooth and bright with hardly a mark.

 

[zinj]

On the right side of the barrel there should be a series of asterisks (*). The number of them denotes the choke.

*: Full
*-: Improved Modified
**: Modified
**- Improved Cylinder
***: Cylinder

 

[Chumango]

Thanks, that solves the mystery. It looks like it is full choke.

 

[Capstick1]

Another way of figuring out the choke of a barrel is with a dime. If you take a dime and put it on the muzzle of a 12ga and it doesn't fall through, then chances are it's at least a full choke barrel. Your on your own as far as figuring out whether it's a modified or improved cylinder because a dime will fall through with both those type of chokes.

 

[Pete409]

"Another way of figuring out the choke of a barrel is with a dime. If you take a dime and put it on the muzzle of a 12ga and it doesn't fall through, then chances are it's at least a full choke barrel. "

That's an old wive's tale that has been disproven many times. I just measured a dime and it is 0.704" in diameter.

The nominal bore of a 12 gauge is 0.729" although this varies from manufacturer to manufacturer. So if we subtract 0.704" from 0.729", we get a constriction of only 0.025" which is only a little more than a Modified choke.

Until very recently, Beretta made their 12 gauge bores about 0.722", so a choke of only 0.018" or slightly more would stop a dime from falling through.