I'm not really qualified to answer genuine gunsmithing type questions, but if it were me, I suppose I would look first at the bore an absolutely ensure that it's not full of lead from a previous owner. If the pistol has eaten jacketed ammo for it's entire life, this will not be an issue, but if someone else had fed it lead bullet ammo, especially lead bullet ammo that wasn't well-suited to that bore, it could be full of lead which will even more than disturb potential accuracy.

If that definitely isn't the case, I would inspect the relationship of the barrel to the bushing. Unlike a 3rd Gen pistol, the bushing on full size 1st and 2nd Gen 9mm S&W pistols is a removable part, comes out as part of a routine field strip.

The barrel bushing is an obviously key part to putting the pistol back in a "repeatable" lock-up. If there is excessive play then the barrel cannot necessarily get placed back in the "SAME" spot for the next shot.

I would genuinely doubt that wear has made the bushing loose, I would suspect more that it was never a very good fit from the start if it happens to be the case. I would try other S&W 1st/2nd Gen barrel bushings to see if you can close the tolerance and relationship to the barrel.

The best way to do something like this would be to field strip other 1st/2nd Gen S&W pistols that you may own and check for fit. Obviously, if you have no others, that's not an option. Tracking down and buying other bushings is certainly possible but we'd be talking about parts that haven't been made since the late 1980's. They aren't totally rare, but won't be find easily either.

Good luck, please report back and I'm eager to hear other suggestions as well.