Couple questions.. Were these new or used shotguns? Was this a dealer on GB or a private party? Why did you force a barrel on a receiver, ( with much force... ) Are you sure it's the proper barrel for that action?
Re: choke tubes - Is this the Tournament Skeet? In any case, EXT choke tubes frequently work loose on most guns. When on the trap line I check mine after each station during the switch (SKB O/U).. Most of the time they're tight, but a few times I note a quarter-turn is needed to bring 'em back to the seat..
If you want to keep 'em in place (at least for a few days) apply a couple drops of blue locktite..
