Possible Gas/Flame Cutting on S&W 642

[Stormin.40]

I have attached a picture of what I think is the beginning of gas or flame cutting but don't know for sure, anythoughts? The picture is of the top strap, bottom side view just above the barrel. This is not lead build up but is actually in indention in the strap not raised. The gun shoots well and is accurate with the exception of factory Wad Cutters I purchased, these keyholed and leaded the barrel badly.

I have only put 15 rounds of +P ammo through this gun and another 500-600 of various other loads. Mainly 125 and 158 gr lead bullets with IMR Trailboss.

 

[Guillermo]

"flame cutting" is really unburned powder "sandblasting".

the "+P" is not a factor. (A mild load)

Only 615 rounds is not much to get that kind of damage!

How light are the bullets you typically fire?

 

[Ranger30-06]

I'd try cleaning it off and seeing what remains. It may just be a couple hairs of lead hanging on just to give you a scare.


Flame cutting is more common if you shoot specials in a magnum gun, then switch to magnums without cleaning the chambers. Being a .38 special, I very, very highly doubt your flame cutting the gun as long as you aren't using compressed loads.

 

[Master Blaster]

Flame cutting is more common if you shoot specials in a magnum gun, then switch to magnums without cleaning the chambers. Being a .38 special, I very, very highly doubt your flame cutting the gun as long as you aren't using compressed loads.

What??????

Flame cutting is errosion of the topstrap above the barrel cylinder gap caused by the hot gasses exiting the gap and erroding the metal of the topstrap. It happens in magnum guns shooting high pressure magnum loads, and is usually self limiting, meaning it stops after a bit when you reach a certain depth. On the 642 you have an aluminium topstrap with a fragile painted and laquer finish, so it's probably finish errosion, most likely it will stop as it reaches a certain depth. Its really nothing to worry about. I have a 642 and it shows quite a bit of finish wear and a little errosion like yours.

 

[Ranger30-06]

Sorry for the confusion here Master Blaster, but read around and it's pretty talked about how you shouldn't shoot specials then magnums, but rather the other way around. The way it works is apparently the shorter specials leave a crud ring, then when you shoot magnums after them, it makes the cases difficult to eject, raises pressures, and blows that crud ring through the gun.

 

[Stormin.40]

I have shot about 200 rounds of Lead 125gr RNFP with 4.6grains of Trailboss, 200 rounds of Lead 158gr SWC with 3.8grains Titegroup or 4.0gr Trailboss, & 100 round of 125gr Berry's plated FP with titegroup (don't remember the charge but it was just below +P data). Various factory loads, mainly Magtech 158gr FMJ.

I didn't realize "flame cutting" was more sandblasting than actually melting away the metal. I haven't had any extended range sessons with this revolver, I doubt I have every shot more than 100 rounds without cleaning.

I sent the same picture to Smith and Wesson to see what they think. The customer representative I spoke to sounded concerned so hopefully they can shed some light on the issue.

Master Blaster, knowing yours has shown some wear is comforting, I really like the gun and thought S&W would tell me the same thing you did, "nothing to worry about" maybe by asking for a picture they are just protecting themselves from a potential lawsuit if a gun blew up.

Ranger 30-06, the shiny metal is pitting in the top strap and is not raised indicating that it isn't built up lead residue, there is some lead residue on the sides of the barrel that I haven't taken the time to scrub off.

 

[Steve_NEPhila]

Just tell Smith and Wesson you want them to take a look at it and they will, for free. That way you get factory engineers and gun smiths to pore over it to make sure they can identify the problemm, you win.

I hear people complain all of the time "but they had my gun for weeks." The logical response is... "And?" You have others, right? If you do not, go get some. If you do, stop whining. Customer service is generations ahead now than it was just 10 years ago. These little machines we buy called "guns" come at relatively low cost (compare the cost of a S&W Performance Center revolver and how much a 1000 round case of ammo to feed it costs!) and many of them come with lifetime warranties...

 

[rcmodel]

and blows that crud ring through the gun.

No, it doesn't.

The hard carbon ring from .38's is under the longer .357 Mag case when they are fired.

It ain't going anywhere, except to get ironed in so hard it is dificult to clean it out.

rc

 

[Guillermo]

I didn't realize "flame cutting" was more sandblasting than actually melting away the metal

most people don't.

But the expanding gases, while hot, are not enough to melt the metal.

The unburned powder is abrasive.

For some reason beaded powders seem to be worse.

 

[Stormin.40]

Thank you for all the replys, I spoke with S&W after they reviewed the picture. I was told that this type of wear is normal up to a point, the "cutting" will stop and not go further. They told me that I have nothing to worry about.

That is what I was hoping they would tell me.

 

[Missionary]

Greetings
Back about 1990 the 357 Max was all the rage. It was discovered that light weight bullets 140 grains and under when loaded with powders like 296 were eating into top straps. After about 1000 rounds there was a pronounced cut. Some shooters just kept on shooting past 10,000 rounds and some panicked, sent away thier revolver and ended up with nothing but some cash. Those who kept on shooting found out it was nothing serious and no known revolver ever broke or flew apart.
I seriously dought you are going to see any structural damage on such a mild cartrige as 38 Special that will amount to anything. Yes I shoot 357 max and 375 Supermag and 414 Supermag and 454 Casull. These cartriges produce horendous amounts of flame with powders like 296. But as long as you stick to heavy bullets the cutting is kept to no big deal conditions. I also shoot lots of 357 mag and 38 Special. Some of my revolvers are long used and my last worry with these calibers is a flame cut topstrap. I still shoot a Dan Wesson 357 that has digested thousands of rounds of loads of 296. Yes there is some cutting in the top strap. But I estimate that it will take another 200,000 rounds to get it to any condition I might think it needs to be sent to the factory.
Mike in Peru
Me I would take a dental pick and with a magnifier of some type slowly pick away at that line and see what it really is. If you find a cut in the metal a pencil lead depth then maybe you have some bad metal. But I would suspect all you will find is some cooked finish. There is a saying up in Alaska.. More people die from worrying about bear attacks than ever die in a bear attack.
Mike in Peru

 

[243winxb]

Blast Shield

What does the gap between the barrel and cylinder measure? Blast shield photos.

 

[Stormin.40]

I don't remember the measurement between the barrel and cylinder. I did measure it a couple of years ago and it was in line with S&W specifications. I think my 642 is good to go, any reason I can't continue to shoot 125gr bullets?

That blast shield on the 329 looks pretty bad?

 

[243winxb]

No reason i know of.