Paul, the polymags do fit in the magazine and they fly well out to about 50 yards. After the 50 yard mark it has been my experience that they do not group well. They also are about 1/2 low at 50 yards when compared to the kings (gun is zeroed for kings)
Lelya .22 doesn’t like them. I don’t think I own a airgun that likes them. However I will say when the predator hits it’s target, it’s nasty.