johnmuir2013 Posted August 22 Share Posted August 22 Background Info: At the Illinois State Championship match in Milan Illinois last weekend, on our first stage, my wife's Stoeger Coachgun single trigger 12ga opened on its own after her first shot (right barrel). I purchased this shotgun new on 2023-06-24. After her ST opened up on her, she used my Stoeger Coachgun Supreme double trigger for the rest of the match. I was videoing when it happened, and I've included a frame showing the dang thing opening on her. When it was new, I installed a “Palo Verde Stoeger Top Lever Spring” from Long Hunter. It's adjustable by spacer selection. I chose the least tension without there being any slop in the top lever. It's been working fine that way for a year, but now, out of the blue, it has started opening on its own. My Cowboy load recipe is 7/8 oz #8 shot, 10.7g of Hodgdon Clays, Federal 209A primers. I took it to my local range and shot some Bornaghi 7/8 oz SubSound shells and it opened on its own after the first shot every time. Then I added spacers to the Palo Verde top lever spring to make it the highest spring tension possible. Then went to the range again. The first test was the SubSounds and it failed (opened on its own) 5 out of 5 times. The second test was our cowboy loads and it worked fine 10 out of 10 times. That is, two shells in it but firing the right barrel each time. So, it's sort of still broke but, on the other hand, it works for our purposes. My question: Is it still broke and it's just a matter of time until she gets bit by the dang thing in a match? Is there anything I can do to make it latch closed more tightly? Quote Link to comment Share on other sites More sharing options...
Larsen E. Pettifogger, SASS #32933 Posted August 22 Share Posted August 22 (edited) You are describing the classic symptom of a too lite top lever spring. The spring is the only thing keeping the gun locked. The locking lug is pushed forward by the top lever spring and when the gun fires the locking lug attempts to (in effect) move to the rear by inertia. First check to make sure that no dirt or debris or a random pellet is not lodged where it should not be. Then try some Winchester AA Low Noise Low Recoil shells. If it works OK with them you have probably got it set up OK for cowboy loads. I could not find any subsonic Bornaghi 7/8 loads. The lowest velocity listed on their website and a couple of others is 1200 fps which is substantially hotter than your 10.7 grains of Clays load. Edited August 22 by Larsen E. Pettifogger, SASS #32933 5 1 Quote Link to comment Share on other sites More sharing options...
John Kloehr Posted August 22 Share Posted August 22 (edited) My double trigger Stoeger does the same thing. It was smithed locally before I bought it. Worked fine at first with Winchester AA low noise low recoil (LNLR) shells (I thought) but easily opens with regular AAs. For me, mine did not actually fall open, maybe due to my grip. Took a few events before I realized this was why the second shell only went click. Further testing showed even LNLR would do it if I pulled down on the fore grip. Test carefully LOL, only load one live shell or a live and a dummy. I have considered repairing it myself (having not done it yet, I will let others explain how), or send it to @BoomStick Jay for a complete review. Or maybe trade it out. Besides the springs, the tangs may need some work. This tang work is also a way to ruin an otherwise good firearm. Since SASS rules prohibit mods which disable lockup, I consider mine down until I can trust it not to open. Might try my '97s Saturday or Sunday. I bought 2 a long time ago and have never fired either one. If I can figure one of them out, I might get to a shoot this year. I have a small window of time to maybe do so. Good luck on fixing your's. Figuring out at what recoil it opens and staying well below that is a reasonable "fix" IMO. It should not get worse, but a lightened spring makes this failure more likely. It is an unsafe failure. Edited August 22 by John Kloehr Otto fails to see an actual misspelling! Quote Link to comment Share on other sites More sharing options...
Jackson Haller Posted August 22 Share Posted August 22 How about putting the original springs back in it and seeing how it works? 3 1 Quote Link to comment Share on other sites More sharing options...
Sedalia Dave Posted August 23 Share Posted August 23 Opening that far is a bigger problem than a weak lever spring. As Larson stated, carefully inspect the action for debris. Lead shot can be smashed really flat and hard to see. My gut thinks that something has catastrophically failed. Check the barrel lugs and make sure they are not cracked. Then make sure they are still properly soldered to the barrels. Check that the screws in the forearm are tight. Check the pivot pin and make sure it is tight and not bent. Quote Link to comment Share on other sites More sharing options...
johnmuir2013 Posted August 23 Author Share Posted August 23 Unfortunately, I cut a coil off of the original top lever spring and the top lever still seemed too stiff. So, I cut off another coil and it was too loose. In other words, I ruined the original spring. That’s what prompted me to buy the Palo Verde spring. Quote Link to comment Share on other sites More sharing options...
Dogmeat Dad, SASS #48563L Posted August 23 Share Posted August 23 One other place to check is the ramp on the barrel lug where it contacts the sliding lock that is actuated by the lever. My wife's Stoeger developed a burr there and it prevented the latch from fully engaging. Granted, my wife's Stoeger had a lot more years on it, but she was experiencing the same symptoms. Check the engagement surface of the lug. If there are any burrs, hit them lightly with a file until it is smooth. You don't want to take off material from the lug, just remove any burrs and smooth the surface. If the lug looks smooth, and there are no cracks, then you probably need a heavier spring. 2 Quote Link to comment Share on other sites More sharing options...
Larsen E. Pettifogger, SASS #32933 Posted August 23 Share Posted August 23 Certainly check for defects but how far the gun opens is more dependent on how it is being held. Several years ago a group of shooters showed up at Winter Range and they had removed the locking block completely. With a standing breech and weak ammo it does not take much to hold it closed. Their theory was once the gun had fired all they had to do was reach for their reloads and the barrels would fall open. Quickly reviewed by the rules committee and declared illegal. Stoegers have no trace of QC. One may be bad and the next mediocre. Here are a couple of photos showing problem areas. On many the locking block is bent or warped. In this photo you can see how warped it is by where the light is showing through between the bottom of the locking block and the top of a machined flat surface. With the lug like this if the top lever spring is replaced but no other work done friction from the poorly fitted locking lug may reduce the rearward movement and limit stress on the spring. After a while the lug will wear on the high spots and decrease friction in the receiver but put more stress on the spring. The bright spots on this lug show the wear patterns. To complensate sometimes the spring pressure might need to be increased. It is also possible the spring has weakened just a bit. The green and purple arrows point to where the locking block SHOULD be engaging the locking lugs on the barrels. Notice there is no sign of any wear where the lugs are supposed to engage the barrel. In this photo the white thing is a machined steel plate I made that is the thickness of the water table on the receiver so I could see and measure barrel lug engagement. The forward lug, the green arrow, has zero engagement with the locking block. The rear lug, the purple arrow, shows the rear lug has only a few thousands of an inch engagement. With lug engagement like this it does not take much to bounce the locking block out of engagement with the barrel. 7 6 Quote Link to comment Share on other sites More sharing options...
Buckeye Pete, SASS # 29941 Posted August 23 Share Posted August 23 I bought a single trigger Stoeger coach gun about two years ago. It was stiff as a board out of the box. I installed a Palo Verde spring kit, smoothed off the rough edges on the chambers, made the auto safety a manual safety and took to a monthly match. It worked pretty well. Next month match it started to open up after the first shot like yours. I'm fortunate that I live near Johnny Meadows here in So. Az. I told him the problems I was having and he said he could fix it. He did! He told me that Stoegers are assembled and with little if any hand fitting of parts. The results are pretty common. He fitted the sliding lock (not sure of the correct name) which moves forward in the receiver and engages the locking lugs on the bottom of the barrels. Since he has worked on it, no problems at all and I still have the reduced Palo Verde lever spring in it. Good luck. Buckeye Pete 5 1 Quote Link to comment Share on other sites More sharing options...
John Kloehr Posted August 23 Share Posted August 23 @Johnny Meadows,SASS#28485L Is also in my short list of options. Excellent reputation equal to what I said in my previous post.. 1 1 Quote Link to comment Share on other sites More sharing options...
Sam Sackett Posted August 23 Share Posted August 23 There have been several threads on this issue. My Stoeger had the same issue. The cause was that the sliding lock that the referenced spring is pushing on cannot slide forward enough to engage the locking lugs under the barrel. The answer is to file material off of the front of the top lip of the sliding lock where the opening lever runs against it. This will allow the sliding lock to travel further forward, engaging further into the locking lugs. Take a little off at a time, reassemble and try it. Once the sliding lock is able to properly engage the barrel lugs you can go back to using light springs. I did this to mine three years ago and have had no issues since. This explanation sounds confusing, but once you get inside the shot tie it becomes clear ….. HERE IS A PAST POST FROM MARAUDER HIMSELF: The actual problem is inadequate lock up of the action. See: http://marauder.homestead.com/files/stoeger2.html The locking lug only goes about 1/2 way into the locking slot in the barrel. Stoeger uses a stronger spring to make up for this rather than take the time to do the extra fitting to have the locking lug fully engage. It is not something most of us can do, but a knowledgeable smith should be able to do it well. Good luck, Sam Sackett 1 Quote Link to comment Share on other sites More sharing options...
Burt Blade, #25657 Posted August 23 Share Posted August 23 If you happen to have a spare factory mainspring from a Ruger Vaquero or Blackhawk, they fit, at least the older Coachguns. I used one in my first Coachgun. Quote Link to comment Share on other sites More sharing options...
Reverend P. Babcock Chase Posted August 23 Share Posted August 23 Howdy Shotgunners, Larsen's write up here is a good one to understand how a Stoeger is supposed to lock up. If the sliding locking bolt is properly and fully engaging the barrel lugs, a light spring can be employed. Using a very stiff spring to hold the breech closed is wrong. That is Stoegers trick to keep production moving with out spending time to properly fit the key locking parts; hence the (relatively low price.) All the spring is supposed to do is allow the locking bolt to slide into full engagement. I had to relieve the upper part of the forward locking lug recess to allow full engagement. First check that the bolt is fully engaging. If you don't assure that it is you will be cursed with an overly stout spring (and tired thumb). For what it's worth, Rev. Chase 2 Quote Link to comment Share on other sites More sharing options...
Go West Posted August 23 Share Posted August 23 Larsen provided a logical description and photos of the issue. JM did a Stoeger for me that has worked well. It makes sense to provide proper fitting in order to use a lighter spring. 3 Quote Link to comment Share on other sites More sharing options...
The Original Lumpy Gritz Posted August 23 Share Posted August 23 #10 AN washers make better spacers. You can also use a 1911 hammer spring here. Quote Link to comment Share on other sites More sharing options...
Lead Monger Posted August 23 Share Posted August 23 32 minutes ago, The Original Lumpy Gritz said: #10 AN washers make better spacers. You can also use a 1911 hammer spring here. A 1911 hammer spring works great and you can get them in different strengths. Use as many coils as you can without getting coil bind when compressed and the spring will last a long time. 1 Quote Link to comment Share on other sites More sharing options...
johnmuir2013 Posted August 23 Author Share Posted August 23 Ok, so it sounds like I need to work on the locking surfaces to get them to mate better. Using my calipers to compare locking block travel between my good Stoeger and my bad Stoeger, the good Stoeger has 30 thousandths more travel. And just going by feel, on the good Stoeger, I can feel the locking block moving as soon as I begin to push the top-lever. On the bad Stoeger, I can tell that when I first begin to push the top-lever, the locking block is not moving. Then, when I push a little farther, I can feel the locking block move. I've attached a photo of my bad Stoeger's locking block and both Stoeger's rear barrel locking lug for comparison. The bad Stoeger's rear locking lug has a nasty divot in it that's not far from the rear surface. I don't have a machine shop, but I attempted to make a "water table" simulator like Larsen's so I can see where the locking block mates with the locking lugs. My actual "water table" (as Larsen calls it) measures 0.115" think. My simulator measures 0.120" thick. I've included a photo of how things mate up with my "water table" simulator. I'm considering filing the locking bolt where the red arrow is. Quote Link to comment Share on other sites More sharing options...
Sam Sackett Posted August 24 Share Posted August 24 I would NOT file in the position you have indicated with the red arrow. Look closely atbthat spot and you will see a little shiny spot. That spot is the only part of the sliding lock that is engaging the barrel locking lug. If you file it away, you will have zero engagement. Sam Sackett. 2 1 Quote Link to comment Share on other sites More sharing options...
Marauder SASS #13056 Posted August 24 Share Posted August 24 (Larsen, that's for the great explanation and photos.) johnmuir The bottom photo is great. It shows that your system is doing pretty well for the proper length, better than many. The problem is the wear - look at the downward curve of the locking surface. It needs to be straight. So you are in luck and can have a great, strong gun once more. So you need to find a good welder. Have them weld up that curve. Then you can file it down to a good level surface and the locking will be good and will not require a strong spring at all. 1 Quote Link to comment Share on other sites More sharing options...
Tall John Posted August 25 Share Posted August 25 (edited) get rid of the Palo spring! I had the exact same problem with the Palo Spring after about 10 months even with all the washers. Buy a long hunter light spring. Much better on Stidger’s! Order yourself a couple replacement latch locks (part 348) from Numrich before you file anything. They are <$9 and each one is different. I bought three. (See pic) https://www.gunpartscorp.com/products/479670b I shaved a teensy-tiny bit (<.5mm) off the top (short) front edge of the latch lock which allowed the LL to slide a bit further forward which caused a solid lockup but then it wouldn’t open. So then I very gently and gradually filed the lower rear leading edge until it would release from the lug. Problem solved. or you can send it off to on of the smiths and pay $500 with insurance and shipping. I just added a document with my detailed fix. How to fix problems with a Stoeger Supreme Shotgun.pdf Edited August 28 by Tall John Added a file with the fix that worked for me. 1 Quote Link to comment Share on other sites More sharing options...
Reverend P. Babcock Chase Posted August 25 Share Posted August 25 Plus one for Marauder. I kind of thought that the forward locking lug looked odd. It clearly is not providing any lockup in its current state. I wonder if it got peened that way due to the opening on firing issue or if it came that way from the factory. Or if purchased used, some prior owner decided to solve some perceived problem by buggering up the lug. Any way, I'm embarrassed that I didn't mention it before. Rev. Chase Quote Link to comment Share on other sites More sharing options...
johnmuir2013 Posted August 25 Author Share Posted August 25 I got the divot welded (oxy acetylene) this afternoon. I'll file the hump flat tomorrow. 2 Quote Link to comment Share on other sites More sharing options...
Marauder SASS #13056 Posted August 25 Share Posted August 25 8 hours ago, Reverend P. Babcock Chase said: Plus one for Marauder. I kind of thought that the forward locking lug looked odd. It clearly is not providing any lockup in its current state. I wonder if it got peened that way due to the opening on firing issue or if it came that way from the factory. Or if purchased used, some prior owner decided to solve some perceived problem by buggering up the lug. Any way, I'm embarrassed that I didn't mention it before. Rev. Chase Sometimes they are not great when new, but generally because the latch does not go in far enough, there is not enough surface area to hold - thus it wears. When you extend the lock, it significantly increases the life of the lock up. If you weld it up as johmeir is doing, it is MUCH harder and will out last the rest of the gun. 1 Quote Link to comment Share on other sites More sharing options...
The Original Lumpy Gritz Posted August 26 Share Posted August 26 13 hours ago, johnmuir2013 said: I got the divot welded (oxy acetylene) this afternoon. I'll file the hump flat tomorrow. Great job! Quote Link to comment Share on other sites More sharing options...
johnmuir2013 Posted August 26 Author Share Posted August 26 Ok. I filed the weld-hump flat. The barrel seems to lock up fine (no looseness or rattles) and opens fine too. I can't claim victory yet, though. I'll have to take it to the range to try it out. 3 1 Quote Link to comment Share on other sites More sharing options...
johnmuir2013 Posted August 30 Author Share Posted August 30 (edited) Success!!! Yay! Sorry for the delay, but I couldn't get to the range until this morning. Even with the Bornaghi 7/8 oz SubSound shells (hotter than my cowboy loads) and even going back to my original one red spacer on the Palo Verde top-lever spring, it works great now. No more opening on its own. Yee-haw! Wifey dear will be happyl She loves her single trigger Stoeger. Thanks, everybody, for your help. Edited August 31 by johnmuir2013 3 2 Quote Link to comment Share on other sites More sharing options...
The Original Lumpy Gritz Posted August 30 Share Posted August 30 2 hours ago, johnmuir2013 said: Sucess!!! Yay! Sorry for the delay, but I couldn't get to the range until this morning. Even with the Bornaghi 7/8 oz SubSound shells (hotter than my cowboy loads) and even going back to my original one red spacer on the Palo Verde top-lever spring, it works great now. No more opening on its own. Yee-haw! Wifey dear will be happyl She loves her single trigger Stoeger. Thanks, everybody, for your help. Best of news! Quote Link to comment Share on other sites More sharing options...
Abilene Slim SASS 81783 Posted August 30 Share Posted August 30 This has been an informative thread, especially with the photos. Can we get this archived somewhere for future reference? 2 Quote Link to comment Share on other sites More sharing options...
Eyesa Horg Posted August 30 Share Posted August 30 A forum of sorts where all the repair sort of threads could be saved. 1 Quote Link to comment Share on other sites More sharing options...
Tooky Slim Posted September 3 Share Posted September 3 +1 for Abilene Slim and Eyesa , great idea Quote Link to comment Share on other sites More sharing options...
Eyesa Horg Posted September 3 Share Posted September 3 5 minutes ago, Tooky Slim said: +1 for Abilene Slim and Eyesa , great idea Tooky.....you goin to the Great Maine Gunfight this weekend? We'll be there Thursday! Appologies for the hijack. Quote Link to comment Share on other sites More sharing options...
Tooky Slim Posted September 3 Share Posted September 3 No, I didn't know about it, but more importantly, "she who must be obeyed", has some chores planned for me this weekend. I agreed to do them so I'm kinda obliged to actually do them. I'm aiming at Sept.29th in Candia. 1 Quote Link to comment Share on other sites More sharing options...
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