I remember back in the 80’s reading about this round in one of the popular magazines of the time. The idea was that a heavy for caliber projectile traveling as a low velocity would be so unstable that it would tumble upon hitting its target. If I remember correctly the Britsh came up with the idea in their Webley MkIV .38 S&W 38/200 in 1922.
The first record I could find of Western loading this round was in 1927 where it is listed in their 1927 price list. This load continued up until at least the 1981 Winchester-Western catalog. The round is described as a 200 lead inside lubricated Lubaloy bullet. Lubaloy is a thin, mostly copper, wash applied to the bullet.
I don’t remember how I came to acquire this box of nine rounds but I have had it laying around for some time now. As rear as I can tell it was produced in 1977 if the 77 stamped on the box flap is the date as I suspect it is.
At five yards it shot very well out of my S&W 442 Airweight or maybe I just got lucky. Recoil was about on par as a 148gr wadcutter but not as snappy.
I only shot two rounds into some bare gel and only got the velocity off of the first round. Its velocity was 567fps and it penetrated to 18 inches. The permanent wound track showed no tumbling even though it was recovered base forward. The second round penetrated to about an inch more and also show no sign of tumbling and was recovered nose forward.
An interesting round but other than the decent penetration probably not very effective.