Flame cutting on Performance Center 627

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Torian

Torian

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I've put about 200 rounds through my SW 627...everything from 125 grain .38 special to 180 grain leadcast .357 magnums.

As I've been cleaning the weapon, I've noticed what I believe is referred to as "flame cutting" where the cylinder meets the barrel face. It's hard to tell in the pic, but there are actually slight ridges forming on the barrel face.

With Performance Center revolvers...the gap between the cylinder and the barrel face is very tight...like the width of a hair TIGHT. I'm wondering if this is making the flame cutting worse?

In any case...she shoots great...but I'm worried about long-term wear. What do you guys think?

34sfm36.jpg
 
There will always be some amount of flame erosion of metals that are exposed to it. Unburned powder particles can also contribute a sandblasting effect. Generally the area of concern is the top strap directly above the cylinder/barrel gap. That usually takes a huge amount of shooting to become significant (if it ever does). I don't see anything like flame cutting in the picture that would concern me at this point. On the other hand, the barrel face looks to have been left with some burrs from machining that I would want gone.
 
BBBBill said:
There will always be some amount of flame erosion of metals that are exposed to it. Unburned powder particles can also contribute a sandblasting effect. Generally the area of concern is the top strap directly above the cylinder/barrel gap. That usually takes a huge amount of shooting to become significant (if it ever does). I don't see anything like flame cutting in the picture that would concern me at this point. On the other hand, the barrel face looks to have been left with some burrs from machining that I would want gone.
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Thanks for the feedback.

Indeed...I can't quite figure out why the SW Performance Center would spend days tweaking the action of the gun yet leave obvious issues like these burrs on the action.
 
Flame cutting of the top strap is self limiting. At some depth of erosion it gets to a point where the gas pressure and flame temp have no effect any longer.
 
I don't see any flame cutting on the barrel shank face.
I see what looks like a tiny dent where a grain of powder or dirt got smashed against the cylinder.

Speaking of cylinders.
If the barrel shank is gas cutting, the face of the cylinder would be too.

Looks like a thin bur all the way around the outside edge of the barrel shank face in the photo from when they machined it.
If anything was getting flame cut, that would be the first thing to go.

IMO: Perfectly normal.
Keep shooting it, and get back to us after 25,000 rounds or so and we will look at the top strap! :D

rc
 
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Along with rcmodel, I also see no flame cutting. There are some Smith owners who would love to have what you are commenting about, instead of the true flame cutting they are getting.
 
Thanks guys. This was a high-priced revolver, so I just wanted to be certain I wasn't missing some type of issue with the weapon or the ammo I was using.
 
Flame cutting is a hole, not "ridges". Ridges on the barrel or the top strap would most likely be lead deposits, which can be removed with a sharp blade or a steel brush.

Jim
 
Jim K said:
Flame cutting is a hole, not "ridges". Ridges on the barrel or the top strap would most likely be lead deposits, which can be removed with a sharp blade or a steel brush.

Jim
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Aww shucks...now ya'll are really making me feel like an amateur!

JimK, these are small, minute grooves in the metal of the barrel face...that I think have been exacerbated by the tight tolerances and hot 125 grain loads I usually fire. I've been shooting good TMJ type jacketed ammo (save for a couple of leadcast rounds) in the last 200 I've fired. I'm pretty sure this is barrel face erosion not lead deposits.

I could be wrong...but I've attacked these things pretty good with just about every solvent.
 
An old article on .44 Magnum said that after 20,000 rounds the barrel breech was eroded enough that it needed to be set back two turns and a new forcing cone reamed.

Shoot it, fix it, etc.
 
I've got a number of magnum wheel guns that have had thousands of full house loads put through them, and the flame cutting only gets so deep and then stops.

As for your firearm, looks great and I can't see much, if any cutting in the picture. So don't get over concerned if you do see some light flame cutting on the top strap, it's normal.

GS
 
Well, I don't think the barrel-cylinder gap is less than a hair. A hair runs less than .001" while a good b-c gap will be around .007". (Much greater will be too much gas escape, much less will result in binding when the cylinder heats up.)

Looking at the picture again, I assume you mean the marks radiating out from the inside of the forcing cone. I really don't know what could cause that, but I somehow doubt that 200 rounds could cause any gas cutting anywhere. A facing cutter might make that kind of mark, but I am not sure exactly how. Why not print the picture and send it along to S&W asking what could cause that to happen?

Jim
 
Ridges on the barrel or the top strap would most likely be lead deposits, which can be removed with a sharp blade or a steel brush.
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Sharp blade?

STEEL brush?

Seriously???

I'll admit that I have used a steel utensil on some guns. Some that were nice enough that I should have known better at the very moment I picked up the tool.

But after finding what a lead-remover cloth will do to GENTLY AND EFFECTIVELY remove carbon and lead fouling, I've always regretted how I abused those guns - or at least most of them.

Unless you hold the gun in the lowest regard, please don't use a steel tool to clean the area around the cylinder and barrel.

Get one of these, and cut into little squares about the size of a .22 cal patch. Just cut them off as you need them. You will be surprised at how long just one of these will last, and it doesn't loose its "oomph" after its been opened. My teenage nephew gave me one on a lark as Christmas present one year. I waited three years to even open it, and probably would not have even given it a try, except that I was stumped on how to clean up a gun I really wanted to sell.

It just flat works.

leadremovalcloth_zps0293c107.jpg
 
Golly, I really apologize to my guns for actually shooting them. I promise to gently put them to rest in cotton wool every night, with a little kiss to make them feel good.

Jim
 
Jim K said:
Well, I don't think the barrel-cylinder gap is less than a hair. A hair runs less than .001" while a good b-c gap will be around .007". (Much greater will be too much gas escape, much less will result in binding when the cylinder heats up.)

Looking at the picture again, I assume you mean the marks radiating out from the inside of the forcing cone. I really don't know what could cause that, but I somehow doubt that 200 rounds could cause any gas cutting anywhere. A facing cutter might make that kind of mark, but I am not sure exactly how. Why not print the picture and send it along to S&W asking what could cause that to happen?

Jim
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Jim K, you are correct. I'm new with this terminology. What I'm actually referring to is Forcing Cone Erosion.
 
I don't see any forcing cone erosion, either. That usually occurs inside the forcing cone, but could occur on its face. I am really puzzled by those marks; I have never seen anything quite like it.

Jim
 
Jim K said:
I don't see any forcing cone erosion, either. That usually occurs inside the forcing cone, but could occur on its face. I am really puzzled by those marks; I have never seen anything quite like it.

Jim
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I've heard sometimes that slower-burning powders in hot 125 grain loads can partially ignite on the forcing cone itself. If excess powder is still igniting outside of the case, maybe that would explain the markings?
 
My own openion is flame cutting isn't flame cutting at all.

I believe unburned ball powder is blown out the gap at very high velocity and acts much like bead-blasting media against the top strap.

The fact is, if you have any experiance using a gas cutting torch it takes seconds to preheat the surface of the metal hot before any cutting is possible.

The flash from the b/c gap simply doesn't last that long.

rc
 
All of my experience seems to back up rcmodel in this case. The ball powders are basically sandblasting the topstrap and cutting it. The heat and gas happen too quickly but throw in some hot partially burned abrasive little ball grains of burning powder and you can cut steel pretty quickly.

Hence, I avoid ball powders for revolvers. In the 38 special it is probably not an issue. In the 357 mag it is a known problem. In the 357 Maximum it led Ruger to discontinue a great model.
 
I concur that light bullets loaded with ball powders can flamecut the top strap on some revolvers, but that isn't what you are seeing. What you're seeing is a high priced revolver with a barrel that wasn't properly deburred from the factory.


NCsmitty
 
rcmodel said:
My own openion is flame cutting isn't flame cutting at all.

I believe unburned ball powder is blown out the gap at very high velocity and acts much like bead-blasting media against the top strap.

The fact is, if you have any experiance using a gas cutting torch it takes seconds to preheat the surface of the metal hot before any cutting is possible.

The flash from the b/c gap simply doesn't last that long.

rc
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That makes more sense now. In regards to Smitty's comment: I'm trying not to get irritated by this kind of thing...but who the heck is running quality control over at the Performance Center these days.

Not deburring something coming out of the PC shop reeks of ignorance and laziness. Functionally...it doesn't seem to impact the weapon at all...but if all I wanted was function I would have purchased a Ruger GP100 at half the price.
 
Actually, it is both hot gas and unburned powder. It is the same thing that causes throat erosion in rifles, a hot burst of gas and unburned particles being forced through a small gap. In one case that is the barrel-cylinder gap, in the other it is the gap between the momentarily stationary bullet and the barrel throat. Physics says that when a fluid (liquid or gas) is forced through a smaller opening, it speeds up, just like turning an adjustable hose nozzle to reach a more distant flower bed.

That is not quite like an acetylene torch. That fast moving gas is both hotter than a torch and moving a lot faster than the gas from the torch (your acetylene tank doesn't have 35,000 pounds pressure in it - if it does, keep it away from me!).

Jim
 
Jim K said:
Actually, it is both hot gas and unburned powder. It is the same thing that causes throat erosion in rifles, a hot burst of gas and unburned particles being forced through a small gap. In one case that is the barrel-cylinder gap, in the other it is the gap between the momentarily stationary bullet and the barrel throat. Physics says that when a fluid (liquid or gas) is forced through a smaller opening, it speeds up, just like turning an adjustable hose nozzle to reach a more distant flower bed.

That is not quite like an acetylene torch. That fast moving gas is both hotter than a torch and moving a lot faster than the gas from the torch (your acetylene tank doesn't have 35,000 pounds pressure in it - if it does, keep it away from me!).

Jim
Click to expand...
I don't know if this helps at all, but all the loads I've been shooting through this lately have been Underwood ammo...125 grain at 1600 fps. They are zingers. I'm wondering if Kevin Underwood is relegated to using this type of powder to achieve these velocities?

I've always considered his ammo top notch stuff.
 
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