Interesting 5" Pre-27 357 Magnum

[Muley Gil]

That U spring is pretty cool. This is the first time I have ever seen one or even heard of one. I've seen the W spring before, and it just seems overly complicated to manufacture.
I wonder why they didn't continue using the U spring once it was tried and found to work. It eliminates one part (rebound spring) and looks like it should work just fine.
As Arty Johnson would say...
Veeeely INTerestink!

I have read that both the W and U mainsprings tended to weaken over time and didn't rebound as well as the original slide/spring combo.

 

[BC38]

I have read that both the W and U mainsprings tended to weaken over time and didn't rebound as well as the original slide/spring combo.

OK, assuming that is the case, then that makes sense.

 

[TheTinMan]

Richard - thank you for sharing so much in this thread. The interior view of the U-spring is great. I had heard about it but didn’t realize it served as the hammer and rebound spring simultaneously. Your cleaning procedure has been copied (and I doubt I’m alone in doing that). And I always enjoy seeing your “scratched up” treasures.

Chip

 

[RKmesa]

The trigger rebound portion of that spring does not look very efficient. How well does it work?

With the design, consistent with several above comments, I too would be concerned with the longevity... That said, the trigger pull on this one is VERY SMOOOOOTH.

 

[Frailer]

I love it when I learn something new. Fascinating stuff.

 

[RKmesa]

Following up - I just learned that the gun shipped in January 1954. Still no clue as to whether the gun is documented shipping with either the bobbed hammer or the U mainspring - still more work to do.

 

[Bullet Bob]

Thanks for the update

PM sent also.