I had heard of this before, but totally forgot about it. Thanks for bringing it back up. I went out to my garage last night and checked my doohickey drawer. Yep, had a handful of those yellow ones in there. Proceeded to try 'em out in my "cheap" guns first. In the Phoenix HP-22A, they fit right in and eject solidly upon racking the slide. Not much of a pin mark on the rim; could reuse each one several times, I think. In the Jennings J22, same story, though not quite the spring in the ejection; they just fall down through the magazine well (I didn't have a magazine in it.) Then, I tried an old Savage M89 falling-block (single-shot) rifle. Pin mark dang near sliced the anchor's rim, and the anchor is now stuck in the breech. No biggie; I was going to bed anyway, so I set it aside. I'll get it out with the cleaning rod. Later, I'll try this out with my two Rugers (Mk-II and 10/22.)