Posted by John Swensen on December 21, 2000 at 20:58:24:
In Reply to: Head Scratcher & a Pal posted by Steve Dedman on December 21, 2000 at 20:14:58:
Rotary horns have larger bores than pistons, in general, because rotaries have longer leadpipes. With a tapered bore, the further the valves are from the mouthpiece, the larger the bore at the valves.
The bore size is not a terribly accurate method for gauging the size of a horn; witness the .770 186, a 4/4 horn, versus the .750 Chicago York, a 6/4 horn.