Not a machinist either but believe in choke bored button rifled barrels.   

Way I understand Anschutz button rifles with a swell on the blank at the muzzle.  More restiance to the button it does not expand as much as the rest of the barrel leaving a choke.

Most Anschutz they leave the larger diameter outside at the muzzle.  Sporter barrel they turn it off after it's been rifled. 

Correct me if I am wrong.

Boats

Hello Tim,
The 32-40 BRC choked barrel is choked .0005" the last 4" of the barrel. No taper. There is about an 1 1/2" taper before the 4". I think a tighter choke would produce fins and that's a bad thing. Like the rest of us, what I know about the Anschutz barrels I have learned from Boats post. During my competition years my practice OH shooting pardner was a Calif. small bore champ. I saw him shoot MOA at 100yds over and over with his Anschutz rifle. He was and excellent shot and had the equipment to match. 
This 32-40 BRC barrel has excellent run out and the choked buttoned barrel makes it a head to head competition barrel in my opinion. I would have no problem using a standard honed and lapped BRC barrel for competition but this choked barrel will give the shooter an edge! The retest targets were shot with three different powder charges ranging from 14.2grs through a little under 14.8grs of old 4227 powder. I was looking for leading and pressure. The results was a plus. This barrel just wants to shoot. I would like to see this barrel in competition. This 32-40 barrel is also honed after reaming and lapped after rifling. It is also stressed relieved. I have suggested a retail cost of $195.00 + shipping for the choked barrel. The standard BRC barrel is $149.00. I think I have answered your question Tim plus a bit more. Thanks for your question.  Ken

The 32-40 case can build up pressure fast and present problems in older actions. A load of 14.8grs. of 4227 is way to hot for a number of these actions! 14.2grs of 4227 is an excellent load. Just remember modern type steel did not come on line until 1920. BRC uses 4140 and 8620 steel for barrels and actions.