I'm goin' take a shot at 1959-1960. I have a Jazz Fest dated late 1959 that is 5" as shown in the 1960 catalog. If I'm reading it right www.vintagedrumguide.com/ludwig_jazz_fest.htm says there was never a 5 1/2" snare called a Jazz Fest, i.e., it was 5" when first introduced under that name.

It was a long, slow transition. Most Jazz Fests were closer to 5.5" in the early 60's, and most were closer to 5" by the late 60's. The average tends to be 5 3/8". But there's no real cutoff date of when they went from one size to another.

Thanks,

Bill

Interesting. Also on a similar note. I have two pioneer snares here. One in a 1961 and the other is a 1966. Both are 5 1/2"

I was looking for a wmp jazzfest for my 66 ludwig kit. I really prefer the sound of a 5 1/2 .