My 15 year old S&W 586-3 has been relatively lightly used, probably about 10,000 to 15,000 rounds through it- vast majority 38 Specials. My 357s are lightly loaded, a 140 grain Remington JHP @ 1100 FPS. I began noticing what felt like a quick light hit on my left cheek when firing 38s, which was greater when firing 357s. It didnt seem as accurate as it used to be. I figured a forcing cone alignment problem. Wrong. S&W tells me that the barrel cylinder gap is incorrect and it will be necessary to turn the barrel and reset the gap. When I asked what caused the problem, they had no answer. So I just paid up my $75. I keep wondering what would cause the window of a 586 to open up so much? I thought that this gun was designed for regular use with 357 ammo, unlike the S&W 19/66 series. My 38 Special ammo is very lightly loaded and my 357 ammo is also on the light side. Is this sort of frame stretching typical?
Originally posted by surveyor47: My 15 year old S&W 586-3 has been relatively lightly used, probably about 10,000 to 15,000 rounds through it- vast majority 38 Specials. My 357s are lightly loaded, a 140 grain Remington JHP @ 1100 FPS. I began noticing what felt like a quick light hit on my left cheek when firing 38s, which was greater when firing 357s. It didnt seem as accurate as it used to be. I figured a forcing cone alignment problem. Wrong. S&W tells me that the barrel cylinder gap is incorrect and it will be necessary to turn the barrel and reset the gap. When I asked what caused the problem, they had no answer. So I just paid up my $75. I keep wondering what would cause the window of a 586 to open up so much? I thought that this gun was designed for regular use with 357 ammo, unlike the S&W 19/66 series. My 38 Special ammo is very lightly loaded and my 357 ammo is also on the light side. Is this sort of frame stretching typical?
No, it is NOT typical. The typical magnum wear points are erosion of the forcing cone and flame cutting of the top strap above the cone. I never heard of a frame stretching.
Even with maximum loads, your frame distorts well within the elastic limit of the steel. Therefore, it will always return to its original dimension almost instantaneously after firing. Unless, the is an actually cracking or failure of a machine element (threads, for instance) your problem is probably due to wear in the cylinder-yoke bearing surface or wear at the rear of the cylinder at the star where it bears against the rear of the frame.
"...just a clingin' to my Bible and my guns..."
Posts: 108 | Location: State of Maine | Registered: 14 September 2008
If this gun has any real wear, it should be in the cylinder star. It has been dry fired a lot. I just dont see lots of 38s and a few mild magnums causing frame stretching. They made no mention of barrel damage (cracking), just needing to turn the barrel enough to reset the cylinder gap. This gun has been babied.
I shoot the heck out of my Ruger GP100 and while it is otherwise loose as a goose, it locks up tight and shoots very accurately. Now this is the gun that gets the abuse, not the 586.
One of the old time gun writers did some experimentation several years ago. They put an S&W revolver (I can't recall which model, but it was a .357) in a Ransom Rest and chronographed various loads while varying cylinder to barrel gap. As I recall, a hand reamer was used at the breech end of the barrel to sequentially remove stock, thus increasing the gap. I believe they initially turned the barrel back to begin with a gap of 0.001 inch and increased it in 0.001 inch increments to around 0.010 inch. The point of the exercise was that cylinder-barrel gap variation did not seem to make a whole lot of difference in either accuracy or velocity. You didn't mention the gap in your piece. The factory used to shoot (pardon the pun) for about 0.006 gap (cold). This was back in the 1960's and I don't know if they are looking for a tighter gap in more modern pieces or not.
"...just a clingin' to my Bible and my guns..."
Posts: 108 | Location: State of Maine | Registered: 14 September 2008
Just for the fun of it: If you don't happen to have any feeler gauges, a clean piece of U.S. currency is just about 0.004 inch thick. Unload your 586 and clean the front of your cylinder and rear face of your barrel. Close the cylinder and see how many thicknesses of U.S. currency will fit in the gap. One is fine, two is a little wide, and three is probably too much.
"...just a clingin' to my Bible and my guns..."
Posts: 108 | Location: State of Maine | Registered: 14 September 2008
Totally aside from the issue of whether frames stretch, and finding one that has is extremely rare, does your gun have any endshake? If it doesn't, or is still minimal, the frame hasn't stretched. Assuming the topstrap doesn't show significant gas-cutting then there is only one thing that causes a wider than usual barrel-cylinder gap, and that is the file the fitter used in fitting up the gun at the factory. In other words, it has been that way since new. If either the frame had stretched, or the extractor bearing and frame contact surface had worn or been battered sufficiently to result in significantly increased B-C gap, then you would see significant end-shake.
If the factory is willing to set the barrel back to correct B-C gap you can certainly take them up on it, but if it is less than .010-.012 now don't hold your breath that they will do better the next try.
No, not much end shake at all. Pretty normal. Not as tight as my Model 19, but still pretty tight. No gas cutting.
What is the wear issue at the rear of the clyinder? That seems to be the problem area. If that gun has frame stretching, something is definately wrong. I dont think it has had more than 2 or 3 boxes of full power 357s fired through it in its life. Plenty of target loaded 38s. The one area Im really starting to wonder about is my light 357 load, which is 7.5 grains of Unique, WSP primer and a 140 grain Remington JHP. I certainly dont see this load as "hot" in any respect, but I do wonder if the light bullet weight may be increasing stresses on the gun, in the same vein as 125 grain 357s cause problems with K-frames? Im wondering if I should switch to 158 grain jacketed bullets only for 357 loads?
I notice one of the initial symptoms of your problem was feeling a hit on your left cheek when firing certain loads. I wonder if there is a bullet or powder issue here. As you know, the exposed lead at the rear of a bullet actually becomes molten at the time of firing. This effect varies with the particular lead alloy and also with the type and charge of powder. Have you been seeing more lead deposits than usual above the barrel-cylinder gap on the inside of the frame? Do you notice the same effect when firing bullets that have no lead exposed at the base of the bullet? Just a possibility.
"...just a clingin' to my Bible and my guns..."
Posts: 108 | Location: State of Maine | Registered: 14 September 2008
I notice one of the initial symptoms of your problem was feeling a hit on your left cheek when firing certain loads. I wonder if there is a bullet or powder issue here As you know, the exposed lead at the rear of a bullet actually becomes olten at the time of firing. . As you know, the exposed lead at the rear of a bullet actually becomes molten at the time of firing. This effect varies with the particular lead alloy and also with the type and charge of powder. Have you been seeing more lead deposits than usual above the barrel-cylinder gap on the inside of the frame? Do you notice the same effect when firing bullets that have no lead exposed at the base of the bullet? Just a possibility.
Could you please document this statement?
'the world is round everywhere'
Posts: 485 | Location: Indiana | Registered: 18 August 2004
Quite a few years ago, when Nyclad (tm) bullets first came on the market, research was done by one of the gun magazines about the vaporization of lead at the rear of an bullet without a rear covering jacket or gas check. High speed photographs were included showing actual particles of lead (larger than vapor state). I am going to try and find this article. It may even have been in The American Rifleman.
"...just a clingin' to my Bible and my guns..."
Posts: 108 | Location: State of Maine | Registered: 14 September 2008
The following forensic firearms site also give s a good discussion of firearms residue noting that the residue contains not only unburned powder and combustion products but also lead particles released during the firing process.
Got my gun back from S&W today and gave them a call. It turns out that EROSION in the forcing cone is the reason the barrel had to be turned and reset, NOT frame stretching. I asked if lead 38 Specials can do that, to which they said absolutely if you shoot it enough. Apparently, mine has been shot enough to erode the forcing cone. I notice that they did some slicking up while they were at it.
Now my gun is ready for another 18 years of shooting.
This sort of thing (lead particles+vapor, not eroded forcing cones ) is why I don't frequent indoor ranges. That, and seeing the kid who sweeps brass behind the firing line is wearing a HEPA filter. Hmmm
Posts: 192 | Location: Cow Hampshire, USA | Registered: 17 December 2007
) is why I don't frequent indoor ranges. That, and seeing the kid who sweeps brass behind the firing line is wearing a HEPA filter. Hmmm
