Springs

[Pofoo]

Is there a way to know if a spring is bad?
This case is the recoil spring on a Walther PP 7.65/32acp. This is a excellent quality all steel gun, but it's not necessarily a sporting gun that was made to shoot a lot.
So, what to look for? Is there a area that gets hammered when the spring goes soft? Or???

[67Cuda]

Springs are cheap, just change them if you think they are suspect.
No way to check, unless they are obviously damaged.

[ar15barrels]

Is there a way to know if a spring is bad?
This case is the recoil spring on a Walther PP 7.65/32acp.
So, what to look for?
Is there a area that gets hammered when the spring goes soft? Or???

Find out what the specification is for the preload at the installed length.
Then test the preload at the installed length.
A worn out spring will be lower than the spec.

There is also sometimes a free length spec.
Check the free length.
Springs collapse and get shorter in free length when they are worn out.

[67Cuda]

Find out what the specification is for the preload at the installed length.
Then test the preload at the installed length.
A worn out spring will be lower than the spec.

There is also sometimes a free length spec.
Check the free length.
Springs collapse and get shorter in free length when they are worn out.

I imagine firearm makers use custom springs specific to the firearm being manufactured.
Not exactly sure how one would go about getting specs on them.

[CamW]

A new recoil spring for the Walther PP in .32 is $7.89 from Wolff Gunsprings.
Buy a new one and compare the lengths of the springs.

https://www.gunsprings.com/WALTHER/PP%207.65mm/cID1/mID70/dID301

[Pofoo]

Can you really use the length of 2 different brands of springs? Maybe if they claim to be identical to factory specs, but what if they just say "fit" or "for use on"?
I know on cars, suspension springs can look vastly different--taller/shorter, larger diameter "wire", different alloy's, etc-- and still be rated the same.

[Pofoo]

Find out what the specification is for the preload at the installed length.
Then test the preload at the installed length.
A worn out spring will be lower than the spec.

There is also sometimes a free length spec.
Check the free length.
Springs collapse and get shorter in free length when they are worn out.

Makes sense.
Thank you.

[ar15barrels]

Can you really use the length of 2 different brands of springs? Maybe if they claim to be identical to factory specs, but what if they just say "fit" or "for use on"?
I know on cars, suspension springs can look vastly different--taller/shorter, larger diameter "wire", different alloy's, etc-- and still be rated the same.

Preload at installed length is the great equalizer.
Does not matter when the free length or wire diameter or number of coils is if the preload and final loads are what they should be.