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1873 rifle firing pin issues -and fixes


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My Uberti 1873 was giving me problems.  I would often jack out rounds when firing fast, and the rounds would be lightly struck by the firing pin.  I thought I was outrunning the hammer fall, because I also was experiencing minir OBDs very frequently.  I replaced the main hammer spring with stock Wolff  springs, and tightened the tension until it began to adversely stiffen the lever action.  It made a little improvement (less frequent misfires), but did not fully  correct either the OBD or misfire problems.

 

Next, I checked the lever. It appeared to be bent in slightly, judging from bolt closure and lever safety timing, (and also from the fact I discovered it was 0.16" short of even being SASS legal !).  I reformed (opened) the lever, and it corrected the OBD issues, but it still did not correct the cartridge misfires. 

 

Next I looked at the firing pin operation.  I used a matching size twist drill to clean out the crud accumulated in the firing pin recess in the bolt.  It made an improvement, but still did not fully correct the misfire problem.  Misfires (Federal primers) would occur even when the action was operated very slowly.

 

So next, I looked at the firing pin extension.  It showed typical wear along sliding surfaces, but nothing unusual. 

Then I noticed the little sliding key recess in the extension where the fp extension is engaged by tab at the front toggle.  The slot was  VERY roughly machined, showing concentric machining marks.  The articulating surface of the key itself was also very roughly finished.  I wondered if that tiny drag on the extension could be enough to reduce the firing pin extension's forward speed upon firing.  I polished the slot to a mirror surface, using 1500 grit wet-or-dry, wrapped over a needle file.   I also polished the little tab by rubbing it across the same abrasive, flat on a saw table. 

Now, after about 500 rounds, the problem appears to be resolved and the rifle is operating properly.

 

I am just passing this saga along, however useful. 

Edited by Dusty Devil Dale
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3 minutes ago, Dusty Devil Dale said:

My Uberti 1873 was giving me problems.  I would often jack out rounds when firing fast, and the rounds would be lightly struck by the firing pin.  I thought I was outrunning the hammer fall, because I also was experiencing minir OBDs very frequently.  I replaced the main hammer spring with stock Wolff  springs, and tightened the tension until it began to adversely stiffen the lever action.  It made a little improvement (less frequent misfires), but did not fully  correct either the OBD or misfire problems.

 

Next, I checked the lever. It appeared to be bent in slightly, judging from bolt closure and lever safety timing, (and also from the fact I discovered it was 0.16" short of even being SASS legal !).  I reformed (opened) the lever, and it corrected the OBD issues, but it still did not correct the cartridge misfires. 

 

Next I looked at the firing pin operation.  I used a matching size twist drill to clean out the crud accumulated in the firing pin recess in the bolt.  It made an improvement, but still did not fully correct the misfire problem.  Misfires (Federal primers) would occur even when the action was operated very slowly.

 

So next, I looked at the firing pin extension.  It showed typical wear along sliding surfaces, but nothing unusual. 

Then I noticed the little sliding key recess in the extension where the fp extension is engaged by tab at the front toggle.  The slot was  VERY roughly machined, showing concentric machining marks.  The articulating surface of the key itself was also very roughly finished.  I wondered if that tiny drag on the extension could be enough to reduce the firing pin extension's forward speed upon firing.  I polished the slot to a mirror surface, using 1500 grit wet-or-dry, wrapped over a needle file.   I also polished the little tab by rubbing it across the same abrasive, flat on a saw table. 

Now, after about 500 rounds, the problem appears to be resolved and the rifle is operating properly.

 

I am just passing this saga along, however useful. 

How are you getting out of battery's on your 73?

 

The little dimple on the primer is caused by inertia... You didn't pull the trigger...

 

Phantom

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3 minutes ago, Phantom, SASS #54973 said:

How are you getting out of battery's on your 73?

 

The little dimple on the primer is caused by inertia... You didn't pull the trigger...

 

Phantom

Good comment

That would be a logical first  assumption, but in this case,  misfires were commonly occurring even when the bolt was deliberately closed and the rifle test fired.  So in those tests, at least,  inertia played no role.  

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2 minutes ago, Dusty Devil Dale said:

Good comment

That would be a logical first  assumption, but in this case,  misfires were commonly occurring even when the bolt was deliberately closed and the rifle test fired.  So in those tests, at least,  inertia played no role.  

Yeah...guess my 100's of thousands of round through 73's have lead me astray...

 

:lol:

 

And I'd like to know just how your 73 was firing out of battery...so...is your lever safety removed??? If you're over-running the lock time either your Mainspring is a fricken rubber band or you're super human.

 

Phantom

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8 minutes ago, Phantom, SASS #54973 said:

How are you getting out of battery's on your 73?

 

The little dimple on the primer is caused by inertia... You didn't pull the trigger...

 

Phantom

I believe the OBDs were occurring because of either (or a combination) of slow hammer fall, and/or the bent lever preventing full bolt closure, as the lever safety was depressed. 

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21 minutes ago, Dusty Devil Dale said:

I believe the OBDs were occurring because of either (or a combination) of slow hammer fall, and/or the bent lever preventing full bolt closure, as the lever safety was depressed. 

I think you're off base on this, but I'll let others take the lead.

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14 minutes ago, Phantom, SASS #54973 said:

Yeah...guess my 100's of thousands of round through 73's have lead me astray...

 

:lol:

 

And I'd like to know just how your 73 was firing out of battery...so...is your lever safety removed??? If you're over-running the lock time either your Mainspring is a fricken rubber band or you're super human.

 

Phantom

Of the two options you listed, I suspect the mainspring (rather than the Super Human) is more likely.  It was very weak, which was why I replaced it.  You could easily watch the hammer drop.  It had no "snap" to it.  And in some (not all) of the OBD cases, I suspect I re-opened the lever ahead of full hammer contact.  But replacing the mainspring did not fully correct the problem.   

 

The misfires on individual test fires with action closed suggested  issues other than timing.   What is confusing is that you would think a mechanical problem, like failed bolt closure would show up as an OBD every time the rifle was fired. But it happened intermittently.  I thought all of that pointed to firing pin speed and energy.    

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Having just chased a similar light strike issue, and blaming the mainspring as I just converted to a slix spring setup, I'll bet your issue may be more in your firing pin itself. I suspected mine was getting wore enough that is was just a thousandth or two short since generally a very slow and intentional fire would work, but as a I sped up if I moved the lever at all I would get a light strike.

 

Fast forward, changing/fitting a new firing pin was the fix. Following the instructions on a new Slix firing pin I ground the base until the firing pin no longer protruded from the bolt face when nothing is pushing the firing pin extension. 

 

I'll bet your filling at the bolt/firing pin extension connection opened up the travel of the firing pin extension by that critical couple thousandth and is allowing it to drive the firing pin that much further forward now. If your firing pin isn't just below the face of the bolt, this would confirm it. Either way I would say get a new firing pin or have one on hand for when you need it....

 

 

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I had out of battery issues with a 66.  Not related to safety lever spring.  Crud built up in the bolt preventing the firing pin from retracting.  When the bolt went forward, OB occurred.  

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1 hour ago, The Original Lumpy Gritz said:

Deep clean the rifle before doing any 'fixes'.

OLG 

Exactly.

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A bent lever can prevent the toggle links from moving all the way up past top dead center, which is necessary for the gun to be fully in battery.  Depending on how much the lever was bent and where the bend was, it’s possible that closing the (bent) lever fully depressed the lever safety while not raising the links past top dead center, thus leaving the gun in a partial or or full out-of-battery condition all of the time.

 

As an point of reference, even one out of battery discharge can bend the lever.

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2 hours ago, Cypress Sam, SASS #10915 said:

A bent lever can prevent the toggle links from moving all the way up past top dead center, which is necessary for the gun to be fully in battery.  Depending on how much the lever was bent and where the bend was, it’s possible that closing the (bent) lever fully depressed the lever safety while not raising the links past top dead center, thus leaving the gun in a partial or or full out-of-battery condition all of the time.

 

As an point of reference, even one out of battery discharge can bend the lever.

 

That bent lever can result into headspace being too much. Anytime you have failure to fire particularly on a gun that has been modified, the first thing to verify is headspace and firing pin protrusion. Nowhere in your discription did you mention checking these.  

Without that info everything else is just a guess.

Also, it's fairly common to see excessive headspace when these guns have OBD-ed

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NKJ. I’m glad you caught that and posted.  I was only thinking of bent levers contributing to oobd’s.  But those out of battery discharges can certainly affect headspace.

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