These were offered in the 1960's. They were made in two sizes, K and N.
Every time I have seen a muzzle brake for sale I've bought them. So far I've seen 6. I did trade one a long time ago. The top three are all for K-38's and the bottom two are for N frames. I bought the nickel N from a long time Smith & Wesson employee. It is not marked by it clearly is a Smith & Wesson muzzle brake. They are seldom seen accessories.
Every time I have seen a muzzle brake for sale I've bought them. So far I've seen 6. I did trade one a long time ago. The top three are all for K-38's and the bottom two are for N frames. I bought the nickel N from a long time Smith & Wesson employee. It is not marked by it clearly is a Smith & Wesson muzzle brake. They are seldom seen accessories.