Let me know if you have any questions on the Crown shooting slugs.
With the 500mm barrel, 23gr slugs will only go about 870fps for 38fpe. If you're looking for true slug performance, you'll want a 600mm barrel, which should get you around 920fps with 23gr, 43fpe.
This will require high reg pressure, like 150bar and potentially a hammer weight will be needed.
Thanks for the heads up. yeah I was looking at the 600mm barrel, expect my Crown 22 is 500mm. That means I will need to buy the 600mm barrel plus liner. Still contemplating which direction I will go if I am going with slug with 500mm liner. I might have to look at an Impact X .22 600mm lol.