Cast parts compatibility?

[surfgun]

I was going to replace a forged serrated trigger on a M25-3, with a cast smooth trigger (for faster D/A shooting) and found they are not compatible (lacks the three pins around the pivot point) so it would not accept the hand spring from the old trigger). Does anyone know the percentage of cast parts not compatible with the old forged parts in S&W revolvers? This has not been an issue with the 3rd Gen. Automatics (that I know of).

 

[Alk8944]

S&W revolvers do not have any cast parts! They are fabricated by Metal Injection Molding (MIM), which is not a casting process.

With he exception of the screws, mainspring and rebound slide spring there is virtually no interchangeability between forged and MIM guns. In the early MIM guns, where only the trigger and thumbpiece were MIM the triggers were interchangeable. Once they re-designed the lockwork to all MIM, and added the IL and the frame-mounted firing pin, interchangeability pretty well ended.

This applies to the lockwork, not the yoke, cylinder and associated parts.