Having previously discussed the development of the Smith & Wesson L-Frame revolvers at length, it seems appropriate to discuss the 1987 recall and modification of these otherwise excellent firearms, which resulted in the “M”-stamped models of the 581, 586, 681 and 686.
A Distinguished Magnum
As you’ll recall from the previous story, the L-Frame was the creation of talented designer Dick Baker, who sought to build a more robust version of the K-Frame, which would handle a steady diet of powerful Magnum ammunition without the barrel cracking issues that plagued the more svelte revolver. His prototype “Super-K” revolvers proved the concept, and eventually matured into the now-classic L-Frame series of guns—the Distinguished Combat Magnums.
The first Distinguished Combat Magnums (and their fixed sight, Distinguished Service Magnum counterparts) were introduced in 1981 and earned a warm reception from revolver fans. The guns were stronger than the K-Frames which preceded them, but retained the outstanding grip frame and trigger reach dimensions which endeared the K-Frames to many generations of shooters.
Here and gone
The guns were eagerly adopted by many law enforcement agencies, but sadly didn’t get to serve very long in uniform before they were replaced by autopistols. In 1985, just four years after the L-Frame was introduced, the armed forces of the United States adopted the Beretta M9 pistol, hyper-accelerating a trend which was already taking shape before the L-Frame was born. By the end of the decade, most of the L-Frames in service had been retired for square guns chambered in 9mm (and less frequently, .45 ACP).
Although its service life was cut short, the L-Frame was in use long enough to discover a latent problem. Within a few years of its introduction, it became evident there was an incompatibility between the gun and certain types of ammunition which could render the gun inoperable. This wouldn’t do for Smith & Wesson’s newest service revolver, of course.
All tied up
The specific problem is that the metal cup of the primer used in some brands and loads would flow into the hole of the firing pin bushing when the cartridge was fired, thus binding the cylinder on the gun.
In practice, the firing pin would strike the primer and ignite the cartridge, and the internal pressure in the case would deform the primer cup and cause it to blow out in a circular ring surrounding the nose of the firing pin (or, in Smith & Wesson parlance, the “hammer nose”). This ring of material would flow around the sides of the hammer nose and squeeze into the space between the hammer nose and the interior walls of the firing pin bushing, where the hammer nose poked through the frame. This created a mechanical block which would prevent the cylinder from rotating when the trigger was pulled, and prevent the cylinder from opening when the thumb piece was pushed.
In these failures, there was never very much material poking into the bushing, but there was enough to tie up the works and prevent the gun from working properly. In some cases, applying enough force to the trigger would eventually shear off the offending ring and allow the cylinder to rotate again, but this “remedy” could potentially leave metal shards behind in the bushing which could block or jam the hammer nose on a subsequent pull, or fall into the interior of the frame, where they could cause an even more significant malfunction. Similarly, the frozen cylinder could often be forced open with a sharp smack to the starboard side as the thumb piece was simultaneously pushed, but this risked bending and damaging the yoke, in addition to fouling the piece internally.
In the worst cases, the trigger could not be pulled at all, no matter how much force was applied. In one of the two instances where the author personally experienced a stoppage like this, it didn’t matter how much force was applied to the trigger—it just wouldn’t cycle.
One of the things that made this a difficult issue to diagnose is that the problem was inconsistent–it wouldn’t manifest all the time, even with the same gun. It seemed that ammunition selection was a significant factor though, and had a big influence on whether or not this stoppage would occur.
For instance, when the recall was announced, the U.S. Customs Service had already fielded a variant of the L-Frame, and they hadn’t encountered the problem in their guns. Customs had run 20,000 rounds through their test and evaluation samples before approving the gun, and they didn’t see the reverse primer flow issue crop up. Nor did it appear after the guns went into service.
However, that may have been a fortunate byproduct of the ammunition used by Customs. As more data points were collected, and the industry learned more about the problem, it appeared that loads which featured fast-burning powders (and had steep pressure curves) were more likely to bind the gun than cartridges loaded with slower-burning powders. Since Customs had tested their guns with a 158 grain Magnum load, propelled by a slower-burning powder, they simply didn’t see it happen in their guns.
There’s indications that certain “problem loads” were responsible for much of the drama, too. In example, an industry source noted that a major manufacturer’s .357 Magnum 125 grain JHP load developed a reputation in this era for excessive and erratic pressures which were connected to a change in bullet sealant. The sealant (which had previously been used to seal primer pockets, but not bullets) was too sticky, and generated so much resistance that pull forces in excess of 385 pounds were sometimes required to move the bullet out of the case. This generated incredible pressures inside the case after ignition.
The excess pressure cracked forcing cones quickly. In fact, our source advises that he saw brand new K-Frame Smith & Wesson barrels crack in as little as 11 rounds when this particular ammunition was used! In the beefier L-Frame, this pressure didn’t crack forcing cones, but it did seek the path of least resistance, out through the primer hole, and knock the hammer backwards, allowing primer cup material to flow into the firing pin hole in the frame.
It’s important to note that the manufacturer eventually abandoned the use of this sealant, and went to another product that didn’t create such high bullet pull forces and internal pressures, but this was a process that would take some time to play out.
In the meantime, coppers across the United States were left in the difficult position of trying to understand the unpredictable and erratic nature of this problem in their new L-Frame revolvers. While U.S. Customs may not have encountered the problem with the ammunition they used, other agencies weren’t so lucky. Shooting a variety of cartridges from the industry’s most respected brands, their guns were experiencing malfunctions that could be life-threatening if they occurred on duty. A frozen trigger was simply unacceptable in a service gun, and something had to be done about it.
with a little help from my friends
A trusted source has told RevolverGuy that a frustrated Smith & Wesson team contracted with an outside expert for some help in diagnosing the issue with their newest service revolver.
Mr. William C. Davis, a former Small Arms Test Director at the U.S. Army’s Aberdeen Proving Ground, and engineer at the U.S. Army’s Frankford Arsenal, was one of the nation’s leading ballisticians. After retiring from government service, Davis opened Tioga Engineering with his friend and partner Charlie Fagg, a former Rock Island Arsenal weapons engineer. The men and the company had an outstanding reputation in the industry, and were the natural place for Smith & Wesson to go when they needed help with the vexing problem.
Davis apparently determined that the root of the issue was a misplaced hammer pivot pin location. His analysis was that the hammer lacked sufficient mechanical advantage to hold firmly against the base of the cartridge during ignition. Instead of remaining forward, in contact with the primer, as the internal case pressures peaked, the hammer/nose would get pushed rearward as pressures climbed, and thus expose the firing pin hole in the frame bushing. This allowed the primer to flow into the hole, around the nose of the retreating hammer. Davis determined that a slight adjustment in the pivot point for the hammer would allow it to exert enough force against the base of the cartridge that it wouldn’t be moved to the rear as pressures climbed, and the hole in the frame bushing would remain sealed.
A different source, who worked on this project at Smith & Wesson, recalls that Davis simply identified a nagging quality control problem at the company. “The parts were simply out of tolerance,” he recalled. “They weren’t made to the print, which was a very common S&W problem.”
“They hire an outside consultant to tell them, Hey! Make the parts to your own blueprint and they will work!“
With the reputation of their premiere service revolver at stake, Smith & Wesson took the uncomfortable, but necessary, step of issuing a Product Warning and recalling the affected revolvers to fix the cylinder binding issue. In the recall, Smith & Wesson warned that:
Cylinder binding can result from a number of causes, including characteristics of an individual revolver or the use of ammunition which does not conform to industry pressure specifications or is particularly fast burning. Recent developments in ammunition manufacture emphasize the production of .357 Magnum ammunition with increased velocity and greater primer sensitivity.
This was clearly a nod to the lighter 110 and 125 grain .357 Magnum loads that were increasingly popular during this period. The lightweight bullets in these cartridges were propelled by charges of fast-burning powders which gave steeper pressure curves than the heavier, 158 grain loads that were more traditional choices in the first Magnum. These steep curves exacerbated the primer flow issue by causing internal pressures to peak rapidly, while the hammer nose was still in contact with the primer. As previously noted, this condition could be significantly aggravated by bullet sealants that caused excessive pull forces.
It’s notable that .38 Special cartridges were immune to this problem, because they generated much less pressure than their big brothers. In fact, Smith & Wesson specifically advised in their Product Warning that, “those who need to use their L-Frame revolver . . . prior to modification can safely fire .38 Special ammunition.”
To fix the issue, Smith & Wesson would replace the hammer, hammer nose and firing pin bushing in the affected guns. The hammer nose and corresponding firing pin hole were reduced to eliminate excess clearance, and prevent the backflow of primer material into the frame of the gun. Presumably, the hammer pivot pin hole was either relocated to the place where Baker’s blueprints said it should have been to start with, or to the location that Davis had suggested, if different.
To get this work done, individual owners would have to send their gun to a S&W Warranty Service Center. At first, Smith & Wesson tried to dispatch technicians to large agencies to fix their pool of guns on site, but when it became apparent that the firing pin bushing could not be properly replaced in the field, S&W arranged for agencies to send their guns back to the factory for repair.
The modification made older L-Frame hammer assemblies and hammer noses obsolete, so to ease the pain on gunsmiths and department armorers who had a supply of these parts in inventory, Smith & Wesson offered a return program which allowed them to exchange the old parts for new ones without charge. This did not include the firing pin bushings, however. Although the new L-Frame hammer nose was incompatible with the old bushings, and required the new design bushing, the old bushings could still be safely used on J, K, and N-Frame revolvers, so Smith & Wesson didn’t offer a free exchange on them.
The L-Frame revolvers were new enough at the time that they had only undergone a single engineering (“Dash”) change since they were introduced. Introduced in 1981, the first Dash-1 change didn’t happen until 1986 (Radius stud package, floating hand). As a result, when the 1987 Product Warning was issued, it applied to all “no-Dash” and “Dash-1” models of the 581, 586, 681 and 686 revolvers. Additionally, the special run of 686CS-1 revolvers that were designed for US Customs were also included in the list.
When one of these guns was modified by Smith & Wesson to incorporate the change, they were over stamped with an “M” to denote the service had been performed. Thus, a 686 “no-Dash” became a 686 M, or a 586-1 became a 586-1 M, with the over stamp.
Additionally, Smith & Wesson created a second engineering change for the L-Frames to incorporate the improvements. All new production guns shipped from the factory after 21 August 1987 were marked as “Dash-2” guns (i.e., 686-2) to denote they incorporated the change to the hammer, hammer nose, and bushing.
Today’s owners can thus easily tell if their gun has been modified. Any “no-Dash” or “Dash-1” L-Frame without the “M” overstep has been left unmodified, and any “Dash-2” (or higher) gun was built with the improved parts from the outset.
Some of you may have an unmodified gun in your possession and may be wondering if you should still attempt to have it fixed at this late date.
We’re not collectors here at RevolverGuy, so we can’t advise whether or not an unmodified gun would demand greater interest from a collector than one which has been serviced. We like to shoot our guns here, and it seems to us that it would make sense to get an unmodified gun fixed, to ensure it is reliable with all types of ammunition. However, if collecting is your primary mission, then we’ll have to defer to others to help you with your decision.
If you’ve never experienced this malfunction in your gun, and you plan to continue shooting the same kind of ammunition, then you may consider skipping the repair. If you go this route, we’d encourage you to leave notes behind for your heirs with instructions on the ammunition that is known to be compatible with your unmodified gun–no sense passing on the problem to a new owner that might be ignorant of it.
We would personally lean towards fixing the gun, though. An unmodified gun could be a liability, even if it is not used as a defensive arm. When a cylinder binds on a gun, it could easily create an unsafe situation, even under controlled circumstances. So, if you plan on shooting your gun, we’d encourage you to get it fixed–particularly if you’ve experienced this malfunction before, or have plans to shoot Magnum cartridges loaded with fast-burning powders.
Fortunately, it appears that Smith & Wesson Customer Service is still providing this warranty service. When we made a phone inquiry, the representative advised that customers with affected “No-Dash” or “Dash-1” guns could still get the “M” modification completed by the factory. Contact Smith & Wesson through the contact form on their website, or by calling 1-800-331-0852 between 0800-1700 Eastern Time, Monday through Friday, for more details.
In addition to the factory, there’s a few commercial gunsmiths who can also do the work to modify your revolver, if you’d like. It might be a great idea to send your gun to one of these places if you wanted to get some other custom work done at the same time, such as action work, new sights, a new barrel, or something else.
The first we’d recommend would be Bill Laughridge’s crew at Cylinder & Slide. The folks at Cylinder & Slide advise that they can replace the hammer nose and bushing on your gun, but will not modify or replace the hammer. They have the OEM bushing in stock, and use a Power Custom hammer nose kit to accomplish the repair. As of this writing, they will charge you about $50 for parts, $70 for labor to install, and another $35 to test fire. You’ll also have to pay the shipping costs. For more information about this service, shipping rates, and delivery schedule, reach out to them at firstname.lastname@example.org, 1-800-448-1713, or (402) 721-4277.
Another option would be famed revolver gunsmith Alan Tanaka at AT Custom Gunwork. Alan advises he still has a few of the old parts necessary to complete this modification, and RevolverGuy readers can contact him at email@example.com, or (310) 327-2721 for more information. Alan’s general pricing schedule can be viewed on his website, but you’ll want to discuss the specific cost of this modification with him when you talk to him.
So, if you ever wondered what the little “M” meant on your L-Frame revolver, now you know!
If you’ve got one of the early guns that missed the modification, give some thought to fixing it. The L-Frames are some of the most enjoyable revolvers to shoot, and when the “M” modification is completed on affected guns, it will make the gun even more enjoyable, by eliminating the possibility of a primer flow stoppage.
Have fun and be safe out there!
RevolverGuy would like to thank our friend “Ed” for allowing us to photograph these beautiful guns from his collection. We appreciate you sharing them with us!