Flame Cutting?

[G11354]

Im certain this topic has been beaten to death, but I must ask.

What causes "flame cutting" and how does one avoid it?

Ive heard some say it is the result of regularly using hot loaded ammunition and others say it is the result of using too light of a round resulting in un-burnt powder having a sandblasting effect on the top strap.

 

[maxxhavoc]

Powder (or anything else) being forced through the cylinder gap at extreme pressures will wear through steel. It is generally normal, cosmetic, and self-limiting. I have never heard of failures caused by flame cutting of the top strap. The increased amount of powder needed for lighter weight bullets cause more damage than heavy and slow rounds.

The real issue with fast and hot rounds is forcing cone erosion, which can cause failures. I have only heard of failures from this in K-Frame Smiths, which have a cut down forcing cone on the bottom. If you're worried about that, get a 686, or Ruger, or Taurus, or really anything but a K-Frame Smith. It will still happen with 158gr Magnums, just not as much.

To avoid it entirely, don't shoot revolvers. It happens the most with magnums, but you will get some surface abrasions on a lowly .38spl. Not a cut channel, but it will show abrasions.

 

[Riomouse911]

Indeed, high pressure gas escaping through the barrel/cylinder gap will almost always leave some etching on the top strap over time no matter what the gun or caliber.
I guess this was the big issue with the Ruger .357 Maximum SA revolvers. They apparently were susceptible to flame cutting, and they got negative press for it. Those guns aren’t common, and a nice one is pricy.

 

[BobWright]

I have heard, but not tried, that a coating of graphite will prevent this phenomenon. Someone far more knowledgeable than I suggested simply coating the underside of the top strap with lead from a No.2 lead pencil. I've noticed it on some of my guns, all .357 Magnums, it occurs but goes only so deep and never becomes a problem. I haven't lost any sleep over it. And one Ruger Blackhawk has in excess or 17,000 rounds, mostly pretty hot JHP loads, and there is that groove. It formed some twenty or thirty years ago and has gone no further.

Bob Wright

I stand corrected. It formed over forty years ago.

 

[Walkalong]

Hot, high pressure, high velocity gases, basically the same as a cutting torch. The higher the charge, the higher the pressure, the sooner it gets bad.

 

[Saleen322]

I shot silhouette back int the 1980s and used a 357 SM (Max) Dan Wesson in revolver class. The Dan Wesson had a little longer cylinder than the Ruger so it handled longer rounds. We quickly found that if you kept the bullets 180 grains and heavier, you had no issues beyond cosmetic. But if you shot under 170 grain bullets at speed, the erosion became a problem and it seemed to effect the Ruger a little more because shooting the 200 grain bullets that performed well were a little tougher to get in the Ruger. While the Dan Wessons did well, DW included an extra barrel with all new 357 SM revolvers just in case. I still have my DW 357 SM and the extra barrel is still new. This same issue showed up on some 357 mags where a lot of 125 and lighter bullets were used at magnum velocity. It takes a lot of shooting even with light bullets to get into trouble. YMMV

 

[captain awesome]

so how much of an issue is it with the maximums? I now have a Dan Wesson and a Blackhawk both in 357 max and see the Dan Wesson has it pretty bad. (i have yet to fire it.) Has anyone ever heard of them failing from it? Or welding over it to fix it?

 

[Riomouse911]

Once it's there in the topstrap, it's forever there I believe. Nothing will fill it.

I always thought about a dovetailed-in carbide piece placed into the topstrap over the B/C gap would be tough enough to eliminate the cutting effect..but (naturally) the dovetail cut would weaken the revolver's topstrap and make the whole idea moot.

Based on what was posted earlier if you stick to 180-200 gr .357 Max bullet loads, the cutting effect will be reduced when compared to 158 and lower bullet weight loads. (I hope)

Stay safe!

 

[NIGHTLORD40K]

Flame-cutting ruined this little gem in only 200 rounds.... The Zamak frame was cut almost halfway through the top strap and there was severe frame erosion all the way around the barrel extension. Such a shame as it was a great idea, just made of poor materials. Rossi Princess, 7-shot .22LR, circa 1969.
I've heard the Zamak .38s such as the Rohm and Windicator can have flame-cutting issues as well.

 

[Old Dog]

I've currently got two older S&W 19s and a 66, all of which exhibit mild to moderate flame-cutting. I typically use only 158-grain .38s, sometimes .357, but no matter how much I shoot these revolvers, the situation doesn't get any worse and I sure don't lose any sleep over it. I suspect that if one isn't shooting the hotter 125-grain .357 loads regularly, it's basically only a cosmetic issue. Of course, I've only been shooting K-frames since the late '60s ...

 

[Monac]

Thanks for your post about the Rossi Princess, NIGHTLORD40K. I have an S&W Ladysmith (albeit one with little finish and cut-down barrel) and I've sometimes thought about getting a Rossi for comparison. Maybe not, if shooting is bad for it. Perhaps the short cylinder was the problem. I had a friend with an Arminius 22 revolver, and I don't recall flame cutting being an issue with that. But it had a cylinder long enough for 38 Special.

 

[NIGHTLORD40K]

Thanks for your post about the Rossi Princess, NIGHTLORD40K. I have an S&W Ladysmith (albeit one with little finish and cut-down barrel) and I've sometimes thought about getting a Rossi for comparison. Maybe not, if shooting is bad for it. Perhaps the short cylinder was the problem. I had a friend with an Arminius 22 revolver, and I don't recall flame cutting being an issue with that. But it had a cylinder long enough for 38 Special.

Ironically, I liked the design and concept so much I would love to find a vintage Ladysmith. A palm-sized 7 shot .22.......if only it had been steel -framed, the Princess would have been a real winner!
I don't know if mine was typical of the type, the timing was good and the cylinder gap didn't seem excessive. There wasn't much (if any) of a forcing cone to it though- not sure if that contributed to the accelerated cutting issue.

 

[340PD]

On my S&W 340PD, there is a small metal tab fit into the topstrap to prevent flame cutting the Scandium frame.

 

[Driftwood Johnson]

View attachment 786222
Flame-cutting ruined this little gem in only 200 rounds.... The Zamak frame was cut almost halfway through the top strap and there was severe frame erosion all the way around the barrel extension. Such a shame as it was a great idea, just made of poor materials. Rossi Princess, 7-shot .22LR, circa 1969.
I've heard the Zamak .38s such as the Rohm and Windicator can have flame-cutting issues as well.

Wow, I never saw one of those. Learn something every day.

Sure looks like they were mimicking a Ladysmith. Right down to the way the cylinder was opened by pulling the extractor rod forward. Of course the Ladysmith was only chambered for 22 Longs, not 22 Long Rifles.

And no, I have never been tempted to shoot my Ladysmith with modern 22 Long ammo. Not recommended.