Things I liked: I liked the way these performed, given they are 1/3rd heavier than your standard that you can find on the shelf. I used them in my new Benjamin Marauder Pistol, and was getting 3/4" groups at 50 yards. The average speed was about 620 FPS. I expected this given the weight difference.
I also used them in an older RWS 48 Magnum .22 Air Rifle I have been using for years to take care of small pest on my property. The average speed was 850 FPS & grouping at 50 yards, was 1/2" groups. This gun has always been exceptionally accurate. But it also has a very nice scope on it.
You know what they say, you get what you pay for. Things I would have changed: I would put a little more of a flare at the back for a tighter fit. Otherwise I am not qualified for the design of these pellets. What others should know: I would only use these heavier pellets that produce much higher velocities. Low velocity air guns would have to much drop off. Also use quality air gun scopes, most people do not even realize that your standard scopes can not withstand the vibration created from a air gun. And since when using air guns you generally shooting at shorter distances.
You can shoot at longer distance once you have a much higher quality and higher velocity air gun. I would also suggest using a scope with a parallax.
Things I liked: Accuracy was very good, sub 1" groups at 25 yards from a Benjamin Marauder Pistol. I also used a RWS 48 Magnum and shot 3/8" groups at 50 yards. Both produced consistent velocities for the air gun. The Pistol produced an average of 624 FPS & rifle produced an average of 858 FPS. Very pleased. Things I would have changed: Again as I mentioned about the Kodiaks. More of a flare at the back. But then again I am not an expert in RD for Pellets. What others should know: Not every pellet is going to perform the same in the same air gun. It is up to each individual to perform test with a wide variety to see what your air gun likes and does not like.
And invest in a high quality scope, for the more serious air gunners out their.