Question: Fitting a firing pin spring in SP-01 Shadow

[ardo]

I was cleaning my Shadow last night, and discovered that firing pin spring is broken. I'm pretty sure I ran it like this in my last match, maybe even a few. Obviously, I am going to replace the spring, but here's the question: other than being able to ignite 100% of primers (I use Federal), is there a 'ballpark' test one can do instead of burning through hundreds of rounds of ammo? Sometime ago, a gunsmith showed me a 'pencil test': shoot a pencil straight up from a cocked hammer position. What I can't remember is how high the pencil is supposed to jump.

Sorry if this sounds silly, the gun was originally tuned by a professional, but I don't have time to engage him now, I got a match this coming weekend.

[Andreas]

Factory firing-pin spring and 13# mainspring will light anything. You can get down to 11# or lower with Federal primers if you know what you're doing.

I've never heard of people messing with the firing-pin spring.

If the pencil doesn't jump high enough, then just keep sharpening it until it does.

[kneelingatlas]

If the pencil exits the barrel it's a good sign.

Andreas' advice is sound, if you're using an extended firing pin and a 13# hammer spring you're good, 11.5# Winchester, Federal and maybe CCI, 8.5# is Fed's only.

[ardo]

Thanks guys. I am using extended pin and 13# hammer spring - I didn't know that the FP spring doesn't need tuning. I only use Federal primers.

I'll keep sharpening that pencil LOL.

Edited December 3, 2014 by ardo

[mrpredictable]

CGW recommends a reduced power firing pin spring with lighter hammer springs, also sold in a kit with an extended firing pin.

[ardo]

Well, this is getting interesting. My Shadow is a Canadian Edition. It has been tuned at the factory (or the dealer, not sure), and the FP spring in it is definitely weaker (same length but thinner) than the one that comes with regular Shadows. The original (strong) FP spring was in the box when I got the pistol, along with the original recoil and hammer springs that were also replaced. I also have an older, regular Shadow, so I can say for sure that the spring that broke inside the Cdn Edition is thinner.

I put in the thicker spring, for now, and will take the gun to my range on Friday to try it out. Ideally though, I'd like to get a weaker spring, it must have been put there for a reason.

Edited December 4, 2014 by ardo

[wanderer]

I run a standard firing pin, standard FP spring, 13# main spring and never had an issue with federal primers. or Winchester, or cci.

[CZinZA]

The lighter firing pin spring is often recommended when you install a light hammer spring. I think it actually comes from the cz rami

[ardo]

The lighter firing pin spring is often recommended when you install a light hammer spring. I think it actually comes from the cz rami

Exactly, I just discovered this 5min ago. I will order the Rami spring, thanks for helping!

[CZinZA]

[emoji106]

[gary2232]

If you do not know what hammer spring you have how can you tell . How do you measure the #s of a unmarked spring?

[BeerBaron]

Unless it's marked or colour coded the only way is to use a spring tester.

[kneelingatlas]

I measured the coil diameter of a bunch of new springs and this is what I got:

Recoil springs:

10# - 0.0385"

11# - 0.0390"

12# - 0.0400"

13# - 0.0405"

14# - 0.0415"

CZ Hammer springs:

8.5# - 0.0335"

11.5# - 0.0375"

13# - 0.0390"

EAA Short Hammer Springs:

13# - 0.0285"

14# - 0.0315"

15# - 0.0315"

16# - 0.0315"

22# - 0.0345"

I would imagine there's some variation, but at least it gives you an idea.

[ardo]

If you do not know what hammer spring you have how can you tell . How do you measure the #s of a unmarked spring?

In my case, I did know because I asked the dealer. He told me they put in 11# recoil and 13# main springs. The package came with an additional 11# recoil / 13# main spring set, and had the original (16# or whatever recoil and main spring) in it as well as the original firing pin spring. Otherwise, I wouldn't be able to tell the difference. Unlike kneelingatlas, I don't have the tools accurate enough to measure spring wire thickness, and don't have a spring tester either. I try to keep my springs labeled.

[Bill Nesbitt]

I measured the coil diameter of a bunch of new springs and this is what I got:

Recoil springs:

10# - 0.0385"

11# - 0.0390"

12# - 0.0400"

13# - 0.0405"

14# - 0.0415"

CZ Hammer springs:

8.5# - 0.0335"

11.5# - 0.0375"

13# - 0.0390"

EAA Short Hammer Springs:

13# - 0.0285"

14# - 0.0315"

15# - 0.0315"

16# - 0.0315"

22# - 0.0345"

I would imagine there's some variation, but at least it gives you an idea.

I printed this off and put it in my "CZ Tuning with Dr Atlas" file. Thanks.

[ardo]

Update: Rami spring worked like a charm, no hick-ups after 300 or so rounds.

[CZinZA]

Good stuff