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Discussion Starter · #1 ·
My Springfield Armory 1911 has started to misfire occasionally due to the firing pin not striking the primer hard enough. Do I just need to replace the mainspring? The previous owner self adjusted trigger pull and probably replaced that spring. Hope this is not a repeat of a "too many times asked question" :)
 

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Have you done a detailed cleaning of the gun? That channel can accumulate a lot of crud. A mainspring has a very long life, unless someone has tried to change the trigger pull by shortening it or something else. It is cheap to replace and as the previous poster has said, it is quite easy to just re-spring the entire gun.
 

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The previous owner self adjusted trigger pull and probably replaced that spring.
Are the hammer hooks hitting the sear, slowing the hammer fall?
 

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Poor firing pin hit

For any 1911 that does not use a firing pin block system, it is good to check to see that the hammer is not hitting on the half cock notch against the sear. It is also good to check to see if the hammer is hitting along the inside of the slide before it hits the firing pin.

For Series 80 guns with the firing pin block set up, if the timing is not right, it will cause light firing pin hits.

The standard weight of a 1911 .45 GI mil spec mainspring is 23 pounds. Some competitive shooters will use a lighter mainspring weight if they are using lighter loads.
 

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It's the XX Power firing pin spring and the Titanium firing pin causing this. Get a Caspian S.S. firing pin and new Wolff spring, and you will be good to go. Don't buy the EGW firing pin. It's the same as the Caspian and double the money.
 

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Caspian firing pin

Since Caspian uses a smaller firing pin nose on all their slides, I am wondering if the Springfield the OP is using has the standard size firing pin, and whether a small radius firing pin nose is OK for the Springfield. I would think it should be fine, but just don't have any experience using a smaller firing pin nose in a standard cut hole for a .45 firing pin.
 

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Doesn't SA use a special size FP?
 

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Yup.
I have the Brown .075" steel firing pin in my SAs, not the .065 part used in .38 Supers and some brands of .45 like Caspian.

Other things to check:

I had misfires in a Colt when the end coil of the firing pin spring broke off, stayed in the hole, and dragged on the firing pin.

I had misfires from a too-light mainspring installed as part of a light trigger pull job. 23 lbs is GI but I have never had a failure with a 19. 15 or even 17 may not be enough.
 

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Springfield Armory uses a proprietary firing pin as Jim mentions. Ti and .075", do not use a steel 9mm/38sup pin as primer flow can then be a problem. Replace the Ti pin with either the EGW or Ed Brown steel pin of the correct SA diameter.

LOG
 

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Springs can and do go bad prematurely. I've put a 20 main spring in my Springfield MC Operator (not ILS) Worked fine for the first 100 or so rounds then I started get light strikes increasing in frequency until it flat would not fire by 200 rounds.

Most quality springs settle in pretty quickly to their rated weight then usually don't vary much through their normal rated life.

The spring I had in my Springer was not of proper steel or not properly heat treated (read, factory defective)
 

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Discussion Starter · #14 ·
What ammo are you using when this occurs?
I'm shooting reloads, 185gr SWC, 5.2gr Bullseye. Shoot that in all my other 45 semi autos, no problems with feeding, firing, or ejection.

For this question, primers were well seated on the rounds that failed to fire and had light firing pin strikes. They fired on the second attempt.

The previous owner told me he replaced/adjusted the mainspring and sear spring.

I have some new 19lb mainsprings and a new sear spring. For starters, I'm going to replace these two springs and see what happens.

Will report back, but it will be a week or so before I get to it. Thanks for all the replies so far.
 

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Springfield Armory uses a proprietary firing pin as Jim mentions. Ti and .075", do not use a steel 9mm/38sup pin as primer flow can then be a problem. Replace the Ti pin with either the EGW or Ed Brown steel pin of the correct SA diameter.

LOG
All the Springfield pins I've measured from the last few years were .070". These are mostly Custom Shop guns.

I fit EGW pins to three of mine and two friends' recently and they usually had a nice fit at .072"-.073", but one .075" pin dropped right in. I guess the pin really doesn't need to be fit that close, but I made sure it had plenty of room to travel freely in the slide while still being a few thousandths over stock size.

Primer strikes are noticeably a little deeper with a 20lb main and steel pin vs a 23lb main and titanium.
 

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My 2006 vintage springer GI model took a .068 sized firing pin from EGW, the ed brown .075 was too big for it. Gonna have to measure yours OP.

David
 
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