I don't know anything about the Kingslayer but have a 507c-gr on my 20ga and it's stellar. Absolutely love that 32moa circle. 16" circle at 50yds and 8" circle at 25yds, everything inside is getting touched. Helpful to judge distance as well. If a bird gets twice as big as that circle he's inside 50 and in range, you can guarantee it. Absolutely love mine. Wouldn't want anything else.
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