Years ago I was told it isn't so much learning the different mechanism, other than the safety. But that the different pistols, rifles, shotguns, have a different balance point. Getting used to that was the bigger problem.
I have no experience in that myself.
I'm sure that's true. If you're a skilled shooter with one weapon at a variety of ranges and combat conditions, you will not immediately be as effective with a New weapon as you would your old one.
But would you be as ineffective as someone off the street that's never fired any kind of gun at any range or in any combat conditions? I find at hard to believe.
Also does the fact that this new gun is a shotgun make all that more difference than if it's a differently balanced, different caliber rifle such as e.g going from a bullpup 5.56 to a traditional layout 7.62? I have my doubts that the it is so much greater that your skill should be reset to zero.
That's the issue. I think too much time is spent picking on technical differences without considering the many, many overlaps in the huge variety of techniques and skills that make up combat effectiveness with any firearm.
Simon Hibbs