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Thread: S&W and the forcing cone cracking issue

  1. #1
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    S&W and the forcing cone cracking issue

    From what I understand, the whole S&W cracked forcing cone issue came from people shooing hot 125gr 357 mag loads in their K frame Model 19s. Does this issue exist in other S&W revolvers such as in the L and N frames? For example, could you shoot hot 125gr 357 mag loads in a Model 619 (L frame) or a Model 28 (N frame), or hot 185gr 44 mag loads in a Model 629 (Also N frame) without any concern?
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    Boolit Grand Master tazman's Avatar
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    Not to my knowledge. The model 19 had a flat spot on the bottom of the barrel beneath the forcing cone directly in front of the cylinder. It was there to provide clearance between the barrel and the cylinder gas shield. This created a weak spot and was where the majority of the cracks occurred. I cracked one there.
    I don't believe any of the larger frames suffer from this design problem.

    What you get with the larger frames is gas cutting the top strap from those same light bullet magnum loads.

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    The 686 was designed to fix that very problem..........
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    Boolit Grand Master Outpost75's Avatar
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    WW2 .38 Victory models also had the barrel flat at 6:00 to clear the cylinder gas ring.

    Split forcing cones are very common in Victory models if they continued to be shot after they have gone out of time and had not been repaired. The WW2-era 158-grain FMJ military round was loaded to higher pressure than common police service 158-grain LRN of that era, in order to maintain standard velocity given the increased bore drag of the jacketed bullet. While I have not measured pressures in WW2 FMJ .38 Special ammunition, its pressures probably equalled or exceeded modern +P.
    Last edited by Outpost75; 03-16-2020 at 02:22 PM.
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    Quote Originally Posted by am44mag View Post
    From what I understand, the whole S&W cracked forcing cone issue came from people shooing hot 125gr 357 mag loads in their K frame Model 19s. Does this issue exist in other S&W revolvers such as in the L and N frames? For example, could you shoot hot 125gr 357 mag loads in a Model 619 (L frame) or a Model 28 (N frame), or hot 185gr 44 mag loads in a Model 629 (Also N frame) without any concern?
    am44mag - this horse has been beat to death many times over but it is a genuine issue. The 357 Magnum was originally confined to the large frame revolvers (N-frame) but eventually the K-frames were designed to handle the 357 magnum and the model 19 was born. This was followed by the other magnum K-frames such as the models 13, 65 and 66.
    In my opinion, the magnum K-frames were "A Bridge Too Far". With 38 Specials used for the bulk of the shooting and limited use of 357 magnum rounds - the concept worked. But the K-frame was never suited for long term use of magnum rounds. The 125 grain and 110 grain bullets are the hardest on the K-frames due in part to the short bullets and flame cutting.
    The K-frame requires a flat cut on the barrel shank at the 6 - O'clock position to clear the cylinder hub (gas ring) on the front of the cylinder. That reduces the cross section of the barrel shank at that position and forcing cone cracks will often appear at that location.

    S&W finally addressed this issue with the introduction of the L-frames in 1981.

    So, to answer your question - can 125 gr 357 mag loads or 185 gr 44 mag loads be shot in the appropriate N & L frames without harm? The answer is the N & L frame are far better at handling those loads than the K-frames, in part, because they lack that flat cut at the 6 O'clock position of the forcing cone. The N & L frames are also larger in general than the K-frame and the gun is just stronger overall.

    As much as I respect the late Bill Jordan, I don't think the S&W K-frame was a suitable candidate for long term use of .357 Magnums.
    S&W put a lot of effort and engineering into making the existing K-frame platform work with the magnum cartridges. In hindsight, they probably should have started with a blank page and developed the L-frame back in the mid 1950's.
    I can't blame S&W for trying to squeeze the 357 mag into a K-frame because the conventional wisdom of the day was to practice with 38 Specials and only shoot magnums on occasion.

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    Quote Originally Posted by Petrol & Powder View Post
    As much as I respect the late Bill Jordan, I don't think the S&W K-frame was a suitable candidate for long term use of .357 Magnums.
    Bill never said the Model 19 was suitable for long term Magnum use. He knew the limitations of the platform at the beginning, no doubt from S&W engineer warnings (and I bet that crew was horrified at what was going to be manufactured). In fact in his book "No Second Place Winner" he states on page 77 speaking of the N-frame Magnums vs the Model 19, "In effect, you have in one a heavy .357 Magnum which will fire .38 Special loads, and in the other a light .38 Special which will fire the Magnum load." On the same page he stated that officers will fire hundreds of .38 Special loads for every Magnum round fired.

    Experience has borne that position out. I've worn out a really nice 19-3 as a 20 something street cop shooting several thousand of those through the gun, destroying timing and end shake dimensions. I should've listened to Jordan. I still love the Model 19 4" the very best of all the revolvers, but I don't shoot them much and never with a Magnum load anymore.
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    Wayne, I agree with everything you wrote.
    Regardless of what Bill Jordan said, once S&W released the magnum K-frames to the public, they lost control over how those guns would be used.
    I think if S&W had developed something along the lines of the L-frame back in 1955, everyone would have been happy.

    The N-frame was excessively large for the 357 Magnum, which gave it a lot of strength but that strength came with weight & bulk.
    With a lot of engineering, the K-frame could be made to work with the 357 Magnum but the magnum loadings were really stretching the limits of that platform.

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    My late FIL split the rear of his M19's barrel. S&W replaced the barrel, but sent a letter warning about using high velocity 125 gr HP bullets, especially after using cast lead bullets without using a Lewis lead remover to clean the lead residue out of the forcing cone. I now own the M19, and don't exceed 38+P loads.

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    For the record, S&W K frame 357's are Model 13, 19, 65, and 66. All are know to have that tendency and in my opinion should be shot with 158 gr + bullets and use of ball powders minimized. They also remain some of the handiest 357 ever made.
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  10. #10
    For two decades I used my M19 exclusively with heavy charges of 2400 powder, typically 13.5 grains, and both cast and jacketed 158 grain bullets. Eventually the cylinder axis pin became elongated, making it difficult to close the cylinder and requiring replacement, but I have yet to crack the forcing cone.

    This conclusively proves that a single revolver within a narrowly defined usage pattern has yet to crack its forcing cone. Beyond that I would speculate that clean living and eschewing light bullets has led to my (so far) success.

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    Boolit Buddy mustanggt's Avatar
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    Last year I finally found a M29-3 with 8 3/8" barrel. It looked almost brand new. I shot about 100 rounds over two weekends of my hand loads with a 250gr Keith boolit. The powder charges were just 44sp +P in 44mag cases. Cracked right at 6 o'clock. Sent it to S&W and I got a brand new -10 with 6 1/2" barrel. I was disappointed to be sure but it is a nice revolver but I can't shoot a handgun worth a damn still so it doesn't matter.
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    Ah, I wasn't aware of the flat cut on the bottom of K frame forcing cones. It makes sense that it would be a weak spot. The main reason for this thread was that I basically had a Model 28-2 fall into my lap, and I wanted to make sure that it would not be harmed by the hot 125gr defensive loads I use in my Ruger SP101. It was also to better educate myself on the realities of this issue. I hear about it from time to time, but have never read a good description of why the issue exists and in what guns it's a possibility in. I had a feeling that larger frame guns wouldn't have the same issues as the K frames. Looking at the forcing cone on my 28-2, it's absolutely massive.

    Thank you for the info fellas.
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    Quote Originally Posted by mustanggt View Post
    Last year I finally found a M29-3 with 8 3/8" barrel. It looked almost brand new. I shot about 100 rounds over two weekends of my hand loads with a 250gr Keith boolit. The powder charges were just 44sp +P in 44mag cases. Cracked right at 6 o'clock. Sent it to S&W and I got a brand new -10 with 6 1/2" barrel. I was disappointed to be sure but it is a nice revolver but I can't shoot a handgun worth a damn still so it doesn't matter.
    That's odd that it would do that with such a "mild" loading. I'm curious if there wasn't some kind of defect in the barrel, or if the crack was already starting but too small to see before you started shooting. I shoot mainly mid to upper end 44 mag loads in my 629-8. It's nice that S&W took care of you. I had a issue with mine (hammer push off), and they took good care of me. I've always admired their craftsmanship, but their customer service really pushed me over the edge to being a major fan of their revolvers.
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    Boolit Buddy mustanggt's Avatar
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    That's the conclusion I came up with too. It was intended to be a mate to my 27-2 model with same barrel length. S&W did take care of me and that meant a lot to me. I am a customer for life. I have many of their handguns all I am happy with.
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    Quote Originally Posted by Outpost75 View Post
    WW2 .38 Victory models also had the barrel flat at 6:00 to clear the cylinder gas ring.

    Split forcing cones are very common in Victory models if they continued to be shot after they have gone out of time and had not been repaired. The WW2-era 158-grain FMJ military round was loaded to higher pressure than common police service 158-grain LRN of that era, in order to maintain standard velocity given the increased bore drag of the jacketed bullet. While I have not measured pressures in WW2 FMJ .38 Special ammunition, its pressures probably equalled or exceeded modern +P.
    I have a WW2 victory that I change the barrel because of a cracked forcing cone. Double action it locks up fine but slowly cocking in single action doesn’t always lock. I have repaired Colts by stretching the hand. Does someone know what the recommended fix is for the S&W? Thanks.

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    Boolit Grand Master Outpost75's Avatar
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    Quote Originally Posted by smkummer View Post
    I have a WW2 victory that I change the barrel because of a cracked forcing cone. Double action it locks up fine but slowly cocking in single action doesn’t always lock. I have repaired Colts by stretching the hand. Does someone know what the recommended fix is for the S&W? Thanks.
    On the S&W replace the hand with a wider one. Usually it only takes 0.001" if you only have one chamber "slow," seldom requires more than 0.002" unless the gun has been abused.
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    Quote Originally Posted by Outpost75 View Post
    On the S&W replace the hand with a wider one. Usually it only takes 0.001" if you only have one chamber "slow," seldom requires more than 0.002" unless the gun has been abused.
    Ok, thanks. Does anyone know a source for a hand of this vintage?

  18. #18
    Boolit Grand Master Outpost75's Avatar
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    Quote Originally Posted by smkummer View Post
    Ok, thanks. Does anyone know a source for a hand of this vintage?

    Gunbroker is a good place to find parts for older S&Ws, also try Numrich, Bob's Gunshop, Jack First. You can usually find a complete set of internal parts, cylinder, yoke and barrel still installed in a cut up frame from a police destruction for under $100. Some sellers will list groups of various parts such as hands, hammers, ejector rods, center pins, etc in groups of six to a dozen.

    Dealing with used hands I advise you to get several, measure yours and try one 0.001" wider, if that doesn't do it try one 0.002 larger, etc. If extractor ratchet is worn or buggered, try swapping it out.
    Last edited by Outpost75; 03-17-2020 at 09:21 PM.
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  19. #19
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    FWIW, the forcing cone of the current K frame magnums are uncircumcised.

    Yeah, I know, they have that thing on the side.

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    Quote Originally Posted by mustanggt View Post
    That's the conclusion I came up with too. It was intended to be a mate to my 27-2 model with same barrel length. S&W did take care of me and that meant a lot to me. I am a customer for life. I have many of their handguns all I am happy with.
    I bought a realy nice 14-3 and shot about 100 rounds and the barrel chipped onthe flat.It was more or less sorry about your luck fromS&W.all they offered was for me to find a barrel an they would install it.

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