S&W mod 27 leading problem

Discussion in 'The Ammo & Reloading Forum' started by oldgunfan, Jan 4, 2009.

  1. oldgunfan

    oldgunfan Member

    Sep 12, 2006
    I have a Smith mod 27-2 that is leading up real bad, yesterday I took my mod 19 smith and the mod 27 to the range I was shooting the same ammo in both 146grn magnus HBWC 3grn win 231, and 158grn LWC 5.2grn unique. I haven't had the mod 27 very long, it was clean before I shot it but I can't remember if I have shot lead in it before, anyway after the shooting session I was cleaning them and the 27 was very leaded up. I used an outers electro cleaner and got almost all of it out, but should I be concerned that the mod-27 was in such bad shape and the mod-19 wasn't. And if so should I send it to smith&Wesson to look at it. Thanks
  2. Oneida Steve

    Oneida Steve Well-Known Member

    Sep 28, 2006
    Upstate NY
    I've been reloading for 30+ years. 3.0 grains of 231 should not be leading up any revolver bore. 5.2 of Unique might be a problem with a soft lead bullet. Maybe.

    There are tens of thousands of 27-2s still in use and leading has never been a problem with them. I would change bullets before sending the gun back to Smith.

  3. oldgunfan

    oldgunfan Member

    Sep 12, 2006
    Yea I was thinking the same thing, I have been loading for maybe 20+ years and although I usually use 2.7grn titegroup with the 148grn HBWC all of my other 38/357's have never had a problem with my loads and the other smith I was shooting that day didn't. I'm starting to think my mod-27 is either out of time or the barrel is tighter, I got it at a gun show about a year ago, It doesn't look like it has been shot much. I'm at a loss.
  4. eka

    eka New Member

    Dec 28, 2008

    It's not your Mod. 27, it's your bullets. They are too small, too hard, the lube is inadequate, or all of the above. Most likely too hard. For a lead bullet to shoot properly and not lead, it has to fit your cylinder throats. If it's too small it will not get a seal as it goes down the barrel, gas blows by, and the gas cutting is what causes the leading. If they are too hard they will not obturate properly and the gas seal is lost and again leading. The hard plastic like lube you find in commercial cast bullets is useless for the most part. Too hard and not enough viscosity. For a cast bullet to work properly it must be sized to match the diameter of your cylinder throats. Ideally the cylinder throats are .001 larger than the groove diameter of your barrel. When you fire a properly fit cast bullet, it leaves the cylinder throat large enough to be swaged down as it enters the forcing cone. It's soft enough to deform at the base and fill out into the grooves of your barrel. The lube aids in forming the gas seal, and all goes well. The problem reloaders run into when they buy commercial cast bullets is they have no control over these critical areas. You might get a good batch and you may not. It's like feeling for the light switch in the dark. There is no real cure all for this other than slugging your cylinder throats and casting your own to fit. Harder is not always better.

    Take care,

  5. Is it leading around the forcing cone or only in one particular place? Try some different lead bullets as EKA suggested. If it leads in one spot only, perhaps the gun timing is off.
  6. muddober

    muddober Active Member

    Sep 19, 2008
    Carson City Nevada
    oldgunfan: I am of the opinion that because the 19 is not leading and the 27 is, it is the gun with the problem and nothing to do with the bullets. Since you know your 19 doesn't have a problem with your ammo I would start by micing (can't spell) the ends of all the chambers of both cylinders and the forcing cone of the 27 paying particular attention to the finish of the forcing cone. My educated guess is that you will find your problem is in the forcing cone, meaning it will be too tight, not enough tapper, very rough or worse it has been "opened up". To properly measure the forcing cone you need to remove the cyclinder as to not ding it and tap a soft lead shortend bullet with a small plastic hammer into the forcing cone and drive it back out from the muzzle end with a wood dowel. Some guys think it is the hot setup to "open up" a perfectly good forcing cone which usually results in ruining the barrel. There is a gun shop in Reno that advertises that he does this to "blue print" the gun as to suggest that the manufaturer didn't have a set of "blue prints" when they built the damm thing.

    As for timming I think that is a bit of a misnomer because unless the bolt is badly worn or the bolt slots in the cylinder are cut wrong the only timming issue would be is the cylinder being turned enough for the bolt to find the slot in the cylinder before you pull the trigger. If it does even when cocking the gun slowly would in my mind put any timming issue to bed other than an improperly cut cylinder, bent frame or misaligned barrel. All highly unlikely.
    Last edited: Jan 5, 2009
  7. oldgunfan

    oldgunfan Member

    Sep 12, 2006
    I took a 375 cleaning jag that fit down the muzzle while it was cocked, and I could feel a small ridge on one side of the cylinder of the mod-27 and I couldn't on the mod-19, I know not the most accurate test but until I have time to make a rod on the lathe that fit's perfect. It's the best I could come up with,I think you know what I'm going to find though. probable everyone is right, forcing cone looks tighter on the 27 than the 19 sooo maybe a little out of time and a bullet thing. I'll let you know, thanks everyone.
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