I just picked up a 20 gauge last week. I am a little disappointed that it will not cycle 20 ga Challengers. It does however cycle Top Gun for some strange reason. I have always thought 20 ga Challengers to be a little on the hot side when shooting them in my O/U with Briley sub-gauge tube, so I thought the Challengers would work in this new gun without a problem.
The top guns will cycle 100%, Challengers will not clear the action. I do have high hopes that the gun will brake in after a flat or two. On the other hand my A400 Eplor in 12 ga functioned right from the first round regardless of what I fed it.