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1911 19lb. mainspring failure


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I had one .45 round with a Winchester primer snap on me twice in a new Springfield 1911.  Almost no dent.

 

I got to looking at the rounds that fired and the dent was so pitiful it was hard to see( don't know how they fired.

 

All I changed in this stock 1911 was I out in an ISMI 19lb. mainspring.  I used that weight in my Kimber for 40,000rds.

I've never seen a 1911 need a 23pounder.  What else could be wrong?  The pin moves freely and protrudes like other guns.

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Really? In a factory gun?  It just looks like stainless steel.

 

But if it is,  I still don't see how there's almost no dent in the primer.  It looks like i"m using an 8 pound mainspring.

 

 

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Maybe I should try the pin from my other SA 1911, It's a full size range officer with the same mainspring.

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15 hours ago, JD45 said:

Really? In a factory gun?  It just looks like stainless steel.

 

But if it is,  I still don't see how there's almost no dent in the primer.  It looks like i"m using an 8 pound mainspring.

 

 

If the spring was that light, you'd feel a significant decrease in the pull weight of the trigger. Remember, hammer spring pressure, pushing on the sear spring, adds significant pressure on the trigger pull weight. I once had the stock hammer spring in a Kimber(23lbs) eventually wear out where it had less pressure than my lightest hammer spring on hand(15lbs). I knew something was wrong when my trigger was almost like a hair trigger with about 1 1/2 lb pull weight, compared to about 4.5-5lb.

Start with substituting the firing pin like you said. Also make sure the firing pin channel is free of oil and carbon buildup. And make sure the firing pin hole doesn't have any deformations.

Edited by Postal Bob
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You said it's a new gun, so I'm going to speculate a little further than the ignition system.  I've had titanium firing pin guns and they ran fine, but you might want to make sure the firing pin return spring isn't also super hard.

 

How's the alignment of the firing pin hole to the primer?  I had a 9mm striker gun (not a 1911) get light strikes because pin was hitting towards the edge of the primer.  Hard to imagine on a large primer, but I have a friend who had the same problem with a 45 Ruger 1911.  Ruger put a new upper on the gun to solve the issue.

 

Are you sure the gun is going into battery properly?  That the brass is sitting properly against the breechface?

Edited by johnmyster
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It's going into battery properly.  Primer dent is dead center.

 

I found some cases fired with the stock 23lb. mainspring. While it was a more full FP dent, it was still weaker and more shallow than any I've seen.

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The easy answer...take it to a competent gunsmith.

Otherwise, many questions.

Does your gun have the ILS (Integral Locking System) mainspring housing?  Replace that with a standard housing and parts.

Is it chambered too deep?  Is the firing pin bent?  What size gauge pin will go through the breech face?  Does the firing pin match that size?   What size gauge pin will fit in the firing pin large bore in the slide?  Is the firing pin dragging in the bore?

Have you made sure the bore in the slide is cleaned out?  What length is your firing pin overall?  Does the firing pin stop center the firing pin in its bore?  What is the protrusion of the firing pin from the stop?  At rest does the hammer push the firing pin in and sit on the firing pin stop or is there slack that allows the hammer to feel loose?  Is the hammer strut pin loose in the hammer where it can drag on the frame (this one drove me crazy with an STI)?   Is the bore in the mainspring housing clean?  Does it allow the plunger to move freely or is it dragging?  Is the bottom housing pin retainer in place? 

 

Sorry for writing a book, but these answers should help solve your problem. 

  

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