My wife has an A400 Xplore 20ga. She has 4 waterfowl seasons behind it now and it is very reliable. I have only seen one morning when it acted up. It was a clear sky with stars galore as we set out decoys. Dawn broke into a blue band of sky with bright orange on the horizon as daybreak got closer. At daybreak we experienced a temperature drop from +4C to 0C. It wasn't that cold and it wasn't damp, our guns were not left out as we set up. They were in their cases in the truck until it was time to park the truck after setting up. At legal time a very light frost started to form on the decoys and a tiny bit on the grass of the blind and barley stubble in the field. After a few flocks had worked and we shot my wifes gun quit cycling on the next flocks. It was down to single shot. My SX3 would cycle(same ammo, 3" Kent Fasteel) but it was as if my bolt was in molasses. I could fire and feel the bolt slide forward in slow motion and hear the click of it locking. I emptied both guns and checked them for dirt, debris etc yet they continued to run the same for about a half hour until the sun fully appeared. I tried cycling them empty and each time her bolt had to be pushed forward to lock it into battery? I came to the conclusion tolerances on the A400 are much tighter than on my SX3. The temp only climbed about 1 degree yet that was all it took to get both guns running perfectly again? It has never happened again and we have hunted in some very cold conditions and much heavier frosts yet something that day about whatever atmospheric conditions were happening shut her gun down.
One thing her gun did not like was Winchester Super Target ammunition for skeet. It will only cycle fully about 50% of the time for the second shot in skeet yet my SX3 will cycle that stuff every time. It definitely has something different about it as it ejects the empties hulls in both guns right at our feet yet Remington Gun Clubs, American Field & Clay, Kent Elites, Federal Top Guns etc both guns throw them 15ft and the loads all have identical payload and published velocities.
That was the first season with the new gun. She has not used it on skeet since so no idea if it's still doing the same or not. Since the factory reccomended break in with up to 250 heavy field loads was completed there has never been an issue in the field. I am anxious to see how it will perform on the skeet field this summer. She has expressed interest in wanting to hone her wingshooting skills on the skeet field this summer.