...and the ever unpopular "bend the barrels" trick has also been seen by me.

A friend had a little sidelock Spanish gun in 28g once that had barrels that 'swooped' up a bit. He was missing high and I tried shooting it. I noticed the barrels being slightly curved up.

I've also straightened some barrels here for a member that were bent from damage. Pretty simple really. An arbor press and some soft wood blocks are all that is needed. Barrels (doubles) can be bent easily and the soldered ribs conform nicely without problems. A weak solder joint may be a problem. But I've not had one with two sets bent/straightened to date.