Originally Posted By: chopperlump
I have always wondered why Mod. 21s have dovetailed instead of chopperlumps. Anyone know? Chops


They used a patent by Frank Burton, 1785765, Dec 23, 1930.
http://www.google.com/patents?id=pF5eAAA...ved=0CDMQ6AEwAA

In the abstract, Burton refers to the "dovetail-grove".

On page 59 of his book, Schwing talks about dovetailing. He says the Burton patent represents a "new system of joining."

Pete