SW 686
On my 686 there seems to be an excessive amount of burn/flame coming out between the cylinder and the barrel. There is even a flame cut just above it on the frame.
I gauged the space between the cylinder and the barrel and it's right at .010, is this correct? I searched the net and didn't find anything on this.
I gauged the space between the cylinder and the barrel and it's right at .010, is this correct? I searched the net and didn't find anything on this.
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.010 seems a little big for the cylinder gap, about .060 seems more like it. It is normal to see a line on the bottom of the top strap just above the gap from flame cutting. 0 -
LL if you mean .006 that might be more like it. I was wondering what SW says it should be?
The flames look great though shooting out the sides. [8D]
I took my son out to the indoor range last saturday. That's how I noticed the flames easier and decided to check things out. I usually(99%)go to the outdoor range where it's not ad noticeable..0 -
For comparison purposes, Freedom Arms have a .001 cylinder / barrel gap.
Followup - If someone finds out if there is any difference in gap tolerances for different frame S&W Guns, I would be very interested to know this. I have an X-frame .460 and it is very wide as compared to my other Smith revolvers. I have always wondered about this, and yes it is new and fired very little.0 -
.357s in particular are notorious for making big fireballs, because the relatively large powder volume doesn't burn entirely within a short pistol barrel. These can be very impressive indoors, particularly from a snubnose revolver.
The inefficient use of powder is the reason why you get such a get a tremendous increase in velocity from a rifle in .357 over a pistol.
Its also a reason why the .357 magnum round has earned a reputation as a gun-wrecker. Unfortunately, its normal to find some degree of flame-cutting in the topstrap of most well-used .357 guns.
Barrel/cylinder gap on a Smith revolver should probably be 0.004-0.006". I think spec was 0.003-0.008".
In general the smaller the gap the better, but too little (less than 0.003") can cause your cylinder to bind up after a few shots from fouling at the breech of the gun.
0.010" would be wider than normal/spec, though not dangerously so. Still a gap that wide will cost you some velocity, and you may see increased "spitting" of unburned powder. It may also contribute to faster frame wear.
When you check it, make sure you check it with the cylinder brought all the way forward and then all the way backward to also measure the "end-shake" (front/back cylinder play).
Excessive end-shake is potentially correctible relatively easily with shims. Reducing the barrel-cylinder gap on a Smith revolver is actually potentially quite an involved job. . .0 -
.004-.006 is a normal gap. The flame cutting should just go so deep and not any more on a stainless frame. Smith is now putting a steel deflector in some of the revolvers to stop flame cutting. 0 -
HM, Iam not sure what Smiths specs are for the gap, but .060 just came to mind. I'll see if I can do some research.
"L" frames are supposed to hold up good over time but any gun can get out of specs.0 -
Hunter Mag, try using a different brand of ammo thru it. You'll find the different powders used in different brands of ammo produces different results in the flash category.
Anyway, one thing to keep an eye out for is top strap erosion. 0.010" is perfectly acceptable, and typically if you shoot lead bullets you want a slightly looser gap anyway, but nothing in excess of .012 if your going to shoot any type of modern or jacketed load.0
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