I picked up my Lightweight 400 from Charlie yesterday and took a few pictures.
What we're comparing is a 1949 or 1950 standard Model 225 "The 400" with a 1955 Model 217 "Lightweight 400". How did they achieve the weight loss?
Just about every way they could!
Having a knowledge of the Buescher horns is helpful to explain it. The standard 400 was made, essentially unchanged, from about 1936 to about 1955. The Lightweight 400 was introduced about 1950 as the Model 227 and was modified sometime thereafter as the Model 217. The Model 227 had a reversed third valve slide and all brass tubing except for the receiver, as near as I can tell. The Model 217 has non-reversed third valve slide and more nickel-silver tubing. Otherwise, no change.
As the entire trumpet and cornet line was redesigned in 1956, this Lightweight 400 was one of the last made.
Mainly, the difference between the standard 400 and Lightweight 400 is the weight of the valve block, the diameter of the valves, and the thickness of the nickel-silver tubing. The bell and mouthpipe appear to be the same between the two versions. The bore is identical.
Since the valves on this Lightweight 400 were rebuilt, the horns will not be a very good comparison, as my standard 400 has valves that are a little loose. It played very well for me in practice this morning, a lot easier to play than my grandfather's 400, whose valves will definitely get rebuilt.
OK, enough yammering, time for pictures! Hope you find them interesting. Note that the engraving was recut and was cut freehand by not necessarily the best guy in the business. But, it's still neat.