I did a test today and was surprised at how inaccurate they were, at 25 yds the 5 shot group fitted into a 2 and quarter inch circle with 3 close together at one inch spread and two "flyers making the group 2 and a quarter inch.

A 5 shot group shot immediately after, with Bisley Magnums was a ragged one hole group covering 3/8 of a inch, so that is why you might as well buy heavy pellets off the shelf. The air rifle was a s-200. The Lem pellets hit very hard so would be devastating on rats at closer range.