The adjustable choke may change the color of the horse. As I continue the research of this shotgun I found that High Standard, Supermatic, Deluxe 20 (ii) was issued with an adjustable choke, and made for Sears. In addition the SN hits on the 583, which is High Standard. There is no indication that Winchester provided the adjustable choke. I will attempt to send, by separate email, a slide showing the 1200 Winchester, and the High Standard.
With what you are describing, the shotgun will suit your purpose. Even after shortening the barrel.
Yes Cyl Bore is a common choke size, however, is normally used in riot, police and deer, (slug) guns.
Crowning the barrel is cutting an angle on the muzzle to release the shot, slug and gasses, from the muzzle at the same time, as each departs the muzzle. If crowning is not accomplished, even in a shotgun, the shot pattern, or slug, could have an irratic grouping on the intended tgt.
Cosmetically it makes the gun look better, and doesn't make it amaturish.
I don't know your capabilities as a machienest or gun smith, or what tools or machines you have, so don't know if you can to crowning at home. I would say probably not.
[This message has been edited by Harley Nolden (edited June 26, 1999).]