Fixing the Stoeger Misfire Problem

As the Stoeger (and other) Side by Side shotguns wear, they will develop a problem with misfires.
Below is a composite discussion from the SASS Wire of the problem and some solutions.

Posted by C. C. Filson, SASS # 62639

Hi pards,

I just got done at a shoot and my Stoeger coach gun got an attitude. The left barrel would some times fire, then the next reload, it won't. I tried some different shells (none were reloads, and primers were not low) There was no showing of a pin strike on the unfired shells, but good strike on the ones that did... HELP....

Posted by Marauder SASS #13056

The likely problems are:

something wrong with firing pin

- They often get shortened and wont fire reliably.

- Burrs can form that hinder their operation.

The gun may be opening slightly after the first shot.

If the gun was tuned with lighter spring for opening the gun, it may show up. The best fix is to make sure the locking lugs fully close. The stronger springs are used to compensate for this, but Coyote Cap describes belowhow to make this work better and still allow lighter springs.

Best overall fixes - new firing pins and make sure the locking system works properly rather than only partially.

Posted by H.H. Hipshot, SASS #26307 on February 04, 2005 03:16 

Another reason may be that the lug that bears on the hinge or pivot pin may be made of soft steel and be deforming. It should be a perfect semicircular cut to fit the hinge pin. If it looks elongated, then it is in the process of failing.

Mine did this with the small amount of usage like you have on yours.

I also had the problem with the gun unlatching slightly after the first barrel was fired. Guess that is why IGA puts such a strong spring on the latch. I wound up placing some shims behind the spring before the spring was finally replaced.

Posted by Coyote Cap, SASS Life #14184

Here is some more info on your problem Stoeger.

You can have that lever spring as light as you would like on your Stoeger IGA, as long as the horizontal bolt goes far enough forward to stay engaged on the rear locking lug.

Look at your rear locking lug (facing you as you open the barrels), that mark is caused by the bottom of the horizontal bolt as it makes contact with the cam angle of the lug.

Notice the mark across the cam angle of that locking lug ? It is only about 1/2 way up the cam, right ?

The horizontal bolt spring does not have enough pressure on it (after it is lightened) and also, the bolt is not going far enough forward to stay latched, so after you fire the first barrel, the action will open under recoil.

It is an action/re-action effect caused by the lightened lever spring and loose barrel recoil of firing the first barrel. (it bounces the horizontal bolt rearward and unlocks the action just enough to cause a misfire of the left barrel).

There is a modification for this to cure the problem, and I may have to write an article for the Chronicle to clarify just what to do.

It takes patience and it ain't easy, but when done, the gun works great and fast.


Posted by Christopher Carson, SASS #5676

Well, Cap, believe I see what you're describing!

Been having similar problems with Denver Deb's Stoeger... and problems began about the same time I replaced the mainspring with one from Lee's. Everything seemed to be working fine, so my next thought was about burrs on the pins or in the bushings, or soft pins... I reamed the bushings (didn't look like they needed anything), tried swapping the firing pins/springs to the other barrel (got worse; both barrels malfunctioned), replaced the pins with the steel ones from Longhunters (the originals didn't look bad, mic'ed OK)... And now I've re-replaced the new mainspring with the original.

Ripped though a box of shells pretty fast, but still had ONE mis-fire, left barrel... So I'm still investigating. Sounds right that the locking mechanism is at fault, since changing back to the heavier original mainspring seems to improve the situation.

And now I'm *really* interested in hearing your fix!!

I'm guessing it has to do with some gentle file work, partly to remove the mark caused by the horizonal bolt and partly to allow the horizontal bolt to move all the way forward on the locking lug?

I'm also guessing that it's a combination of gentle file work to get the angle on the underside of the horizontal bolt right -- AS WELL AS on the top side of the locking lug itself?

Posted by Coyote Cap, SASS Life #14184

Chris, you need to take a whole bunch of metal off the front of the upper side of the lever pivot on the horizontal bolt.

I wish I could draw you a picture pard, you would see right away what I was talking about.

Don't go filing away on the locking lugs. That is the wrong thing to do on a soft metal Stoeger.

What I am talking about is real hard to describe, as when you take metal off one place, you have to compensate for that removal of metal at another place.

You physically have to get the horizontal bolt to travel forward quite a bit in order to engage the front locking lug deeper.

If you look at the area on the top of the horizontal bolt that fits into the slot in the lever shaft, you can see how this will effect the forward travel of the bolt if you surface grind away almost 1/16th inch of metal.

As soon as you remove the metal to get the bolt to travel forward more, don't make the mistake of putting the barrel back on until you have removed enough metal from the bottom and front of the forward locking lug, so the bolt will clear the lug and allow the barrels to open.

If you don't watch this closely, the barrels will not open because the bolt is farther forward and you will have to take everything apart again to get the barrels to open.

It is a delicate balance, but once done, the lever spring and bolt spring can be so light, the gun will be a pleasure to shoot.

And it won't open up and misfire anymore !

Posted by Christopher Carson, SASS #5676

Thanks, Cap, I really appreciate that you're taking the time to share all this with us!

I think I understand in principle. Might not get all the details quite as well, though

Got my trusty exploded parts diagram in front of me, looks like the horizontal bolt is named the "lever lock" (Code # C-12-348 for Deb's model).

When you say "take a whole bunch of metal off the front of the upper side of the lever pivot on the horizontal bolt" you mean the place where the rear face of the vertical portion of the "top lever" engages the slot at the rear of the lever lock (horizontal bolt)? Where the top lever hook cams into the horizontal bolt?

I can measure the distance from the mark on the locking lug, sure enough, it's a bunch -- that's the technical term -- so taking that same "bunch" off the leading edge of the hooking? surface of the locking lever/horizontal bolt tracks right in my mind. As you said in your first note, looks tedious, what with having to dismount the whole insides of the action first.

OTOH, also sounds easier than what I was first guessing, since getting the angles right would be a whole lot more trial and error... and since that would have the affect of slimming the locking lever, perhaps not the safest approach.

When you say "don't make the mistake of putting the barrel back on until you have removed enough metal from the bottom and front of the forward locking lug" -- you mean ?really? take metal off the locking lug? Surely not as much as what we take off the locking bolt, right? By bottom and front, you mean the surface facing the receiver, right? I magine that's just a matter of retaining the same angle?

That would in turn mean the "lock impeller" rod will probably need to travel further back and forth, which also means all this is likely a good mod to do BEFORE shortening that rod (to change the safety to manual mode), right? (Hmmm... too late, in my case, might have to revisit that later on )

Just had another thought... Why would the manufacturer not already have noticed/fixed this? Or are some guns delivered with a locking bolt that travels all the way forward and mates correctly with the locking lug? If so, seems like that'd be a good way to shop on these guns, at least when viewing in person... If the mark is there, pass...

Regards, -Chris

Posted by Christopher Carson, SASS #5676

Cap, stop me if I've got some of this wrong!

Got a chance to fool with it some more yesterday afternoon... took Denver Deb's Uplander Supreme apart again, removed the "top lever spring" and the "top lever spring guide" -- and the "lever lock" slips right out, so I've begun doing some measurements to see what it'll take.

For clarity, it's called a "lever lock" in Deb's parts diagram; in mine (for the Uplander & Coachgun) it's called the "latch lock" -- and functions as the horizontal locking bolt as Cap describes.

Looks like the leading nose is not square, and dressing that a bit will improve lock-up just a tad anyway.

But the leading edge of the top hook -- where the lever's pivoting motion cams the piece backwards to unlock -- has about .03" to .04" of extra metal. That in turn keeps the bolt from sliding far enough forward to fully engage the locking lugs.

It may require more adjustment after that, but I'll have to do some trial-and-error fitting at that point. Think that's where Cap means the "patience" had better come into play

Posted by Coyote Cap, SASS Life #14184

"Chris" Here is a tip !

With the barrel off the frame, align the barrel with the outside of the frame, (just like it was installed.

This will allow you to "see" how the horizontal bolt aligns itself with the front and rear locking lugs.

This idea also works well with the barrel in the "tipped up" (open) position. This way it is a lot easier to install lock-up notches in the forward locking lug and to get the horizontal bolt (forward facing) angle correct.

"Cap" (who has done it all wrong before too) !

Posted by Christopher Carson, SASS #5676

PATIENCE, Cap says!

Yep, IF I fixed it, it wasn't difficult, just slooooooowwwww... Ground off enough of the top of the bolt (latch lock) so it would travel almost .10" further forward -- the distance required to fully seat in the locking lugs. That was the easiest part, since I could use a power tool.

Then fitting the bolt angles with the locking lugs and fitting it so the gun would actually unlock after all that took the most time. Hand filing sure doesn't go all that fast

One surprise was that as I was homing in on it, working only with the barrels and action and with the lighter top lever spring installed, I got to the point where the barrels would only unlock with some kneebone assistance. At that point I put the stock and forend back on, and the barrels immediately unlock with no resistance at all.

Naturally I hope that means I didn't go TOO far with that little file thing!

Haven't test fired, yet, and probably won't get a chance for another couple weeks. So I don't yet know IF I really fixed or not. Still, I'm hopeful...

While I've been working on the thing, I've at least had a chance to examine the design a bit more. Gotta admit, looks like a decent way to build an inexpensive gun. This isn't a Krieghoff nor even a Beretta, SKB, Browning, etc... but for what we do with 'em, and the way we use 'em, it seems to be designed and manufactured inexpensively to suit the purpose most low end guns are designed for: no frills gunning, no worries about cosmetic damage, easy enough to maintain and repair when necessary.

Forgot to mention I also picked up a plain coachgun version at the gunshow the other day. A local dealer was going out of business, this one was new but had some slight rust spots and a shop scratch on the checkering... but he had it marked down sufficiently. I actually walked away three times first, but... well... he came down a tad more...

A little Flitz on it was all it took, and it looks pretty decent now. And now that I've got some time spent inside one of 'em, felt like at least I'd know how to work on it if it needs it

Cheers, -Chris

Posted by OldBoz, SASS #23058

Cap and others-

I have been through this "firing pin sticking out" thing three or four times. Each time I clean out those screw-in bushings in the front, they seem to get tight again and not let the firing pin go back.

So, I am wondering if the metal is just too soft and cobbles right back up? My main question is can I just case harden those two things (Kasenit) and solve the problem?

Posted by Doc McGee, SASS #51213

Old Boz,

I'd check and/or replace the firing pins, the originals can be too soft and mushroom which would make them tighten up. I'd also check how the pins, springs, and such are assembled. If they are not assembled exactly right, there can be problems, too. Check your schematic to make sure you've got them together right.

Do the firing pin return springs seem to be stiff enough to return the pins?

Anyway, I replaced my firing pins with the black anodized stainless firing pins from Longhunter. Viola, no more problems! DTrader and Brownell's also have wrenches for removing the firing pin bushings. I created mine out of some steel scrap and three drill bits that fit the holes in the bushing.

Another thought, do you shoot the Holy Black? Might be crud buildup if you do. Clean well and after every shoot.

Good Luck!

Posted by JD Kid 47083

Hi ya's

Shellie (my other 1/2 ) has a 20G doing the same kinda thing always the left side ,it seems to not be cocking why i don't know if ya take the forestock off ya can cock it and it stays cocked almost seems like the cocking lever (there will be a proper word for it ) is slipping or not going far enough to lock the sears .. almost sounds like the same thing

catch ya

JD Kid

Posted by Coyote Cap, SASS Life #14184


One thing you guys can do is add a very small (low amp) wire weld spot on the underside of the left cocking cam.

Hone it down so that the most metal added would be .025, this should cock the left hammer better, to "set" on the sear better and still release the firing pin from the primer dent.

One trick I do, is to dry fire both barrels, then look very closely at the gap created, just as you start to open the barrels.

What you are looking for is the firing pins sticking through the frame, that you can see clearly, just as you start to open the barrels.

What you want to have happen, is the firing pins to retract (immediately) as you start to open the barrels, because if they do not retract right away, then the chances that the firing pin that is sticking out the longest, will be the one that causes the action to open hard.

The reason, it is sticking in the primer hole.

Now, if you cannot see one of the firing pins sticking out as you open the barrels, then this is the firing pin that is setting back too far and usually what will happen is an occasional misfire on that barrel.

Oh well, there I go again, writing a book on a simple problem. It is a lot easier to show people what is happening, than it is to explain it by typing it out.

Coffee break is over, back to the grind !

Return to Shotgun Page