Stan, I would disagree with your exchangeability of other double gun barrels. I have been shooting a 687EELL Beretta for many years, at one time I had 4 different barrels that all were timed OK. Also exchanged barrels on a different 682 and my son's 680.
The Valmet's did not really take off with the target shooters, went to the same place as Rottweill's and so on....good guns, poor marketing etc....
Mike, I have understood from other shooters that many Berettas will interchange, but notice that I said "I can't say that about any other double gun I have had any dealings with." I do accept your experience. Thanks.
Did Valmet/Tikka actually claim a drop in fit?
Not that I am aware of. I have a close friend who must own upwards of a dozen of them, in all configurations, and has found that to be the case, tho'.
Best, SRH