Hi folks

I'm trying to sort out what Dynasonic snare frames match with what serial numbers to be period correct. I have read many posts on this forum and studied Rob Cook's Rogers Book and the article on Rogers Owners Forum comparing the four frames extensively (and I know there are more than four) but am still having trouble sorting out the frames with the serial numbers and dates.

I am particularly interested to know when Rogers switched from the frames with posts to the blunt end frames - with what approximate serial numbers and the approximate date.

Thanks for your help!