MY THOUGHTS ON FLAME CUTTING - DIDN'T WANT TO HI-JACK PREVIOUS THREAD

[chief38]

There is currently a "Flame Cutting" thread here in this section and my intention was to bring something up but not to hi-jack the original Fella's thread.

I am not a licensed Gun Smith - let me clarify that. However, I am a very mechanically inclined person who prides himself on a "common sense" approach (if it quacks like a duck, swims like a duck, looks like a duck - it's probably a duck)! Guns are just a mechanical metal devise and are not special. They are subject to wear, failure, stress just as anything else man made is.

Most every material I have encountered in life is either purposely torn, sheared or cracked with a scoring mark. Glass, porcelain tiles, Marble, ceramic, rocks, paper, plastic, etc. etc. That is because when something is scored that becomes the weakest point in the structure. That said, steal should react no differently - even though steel does have "a grain to it" which will to some extent be less susceptible, theoretically! When Flame Cutting occurs, most of the time the line it leaves (unless it becomes quite severe) isn't enough to make the top Strap of the Revolver fail. However.... that point still becomes a weak spot! At what point is it deep enough to create a failure - I don't know but it is still a weak spot.

S&W will tell us it's perfectly normal and not to worry about it because they do not want to replace thousands of Revolvers. Remember, the Top Strap requires that the frame be replaced - BIG $$$. They also would open themselves up for law suites and bad press. I suppose the failure rate s so low it's not a concern to the average owner so they chose to make it a non-issue" and have repeated the same slogan for years, "it's normal and will eventually stop and cause no harm". They also count on most owners to stop the use of 125 grain Magnums after they realize what has caused the problem.

So while I am not suggesting that we stop shooting our Revolvers with a score mark from Flame Cutting, I would strongly suggest stopping the use of 125 grain Magnums in it! I would also suggest that anyone who has experienced this or is well aware of the situation should pass the word along to new owners of Revolvers chambered in 357 Magnum - especially the J & K frame models. Prevention is the cure IMO. Again, not saying they are dangerous for the most part if they have a slight score mark, but personally I do not buy into the "it will stop by itself" line! WHY would it magically stop with continued usage of 125 grain bullets? I would also rather own a .357 Revolver WITHOUT a score mark of given a choice.

This is just my own common sense opinion and YMMV. Personally I don't own any 110 or 125 grain Magnum ammo any longer and use 158 & 180 grain bullets instead.

 

[Erocksmash]

I agree with you, I have only ever shot 158gr bullets out of my L-frames. With some flame cutting evident. Your point is very valid as it does create a weak spot. Hard to belive that flame cutting goes to a certain point, then stops?!?! Well it should have started in the first place no?

Mind you old lets say Colts, percussion cap and ball Sa guns.( I'm not really familiar with the specific modelor models) for the longest time did not have a top strap as part of the design so why does it even exist? I understand pressures are different and again I'm speaking out of ignorance because my knowledge only goes so far......

 

[OldK22]

I thought the original other post was pretty silly. Load up a hot load that is flame cutting your revolver and then ask what you should do about it. To me it is like stating that every time you hit your thumb with a sledge hammer it hurts and then asking what you should do about it.

 

[mikerjf]

If I may refer to a well-known principle espoused by author Douglas Adams, we have to consider an exception to this; the now-in-short-supply common roll of toilet paper.

Despite being "scored" with a line of perforations, toilet paper invariably tears at another location. Clearly the perforations have made that area stronger.

IIRC, in Douglas's book, they used this discovery to create a new material which was so perforated it almost no longer existed. The tensile strength increased to an astonishing level, and with virtually all of the material recovered from the perforating process, it could be used to make more material nearly in perpetuity. It was named "Nothing".

Sounds like a heck of a way to make an Airweight!

 

[armorer951]

Considering ignition temperatures between the front of the cylinder and the barrel extension can reach above 2000° F, some damage to nearby resistant metal surfaces is inevitable. The higher the powder charge, the greater extent of the damage.

 

[Rule3]

Perhaps folks should scroll down to the bottom of this thread and read the many other "similar" threads on the same topic. Or better yet search the web for the other GAZILLION thoughts on the subject. Who can or has shot enough magnum 125 grain loads to destroy a revolver??

Gee, has everyone mentioned the different powders out there? Some are more "flame" producing than others.


Lets all just go with "flame cutting is self limiting"

Does anyone know of a verified case beyond a doubt that a gun was shot so much with mag 125 grain loads and actually destroyed the top strap?? One or two anecdotal internet posts is not verified, Like trying to guess why someone had a Kaboom. Without the actual history of ALL thr load data, ammo, powders, bullets used, impossible to verify why a gun was "ruined"

If SW and Ruger made magnum handguns that could be cut in half by shooting FACTORY ammo, they would not still be in business.

 

[pasound]

I have 3 357 chambered revolvers. One Smith, two Rugers. I don't shoot 125gr factory or reloads in any of them because I remember from 30 years ago that those put a basketball sized flame in front of my barrel. Flame cutting nothwithstanding, the flash disturbed any further shots. I buy 158's and reload 158's and 180's.

 

[Abflyboy]

Slightly off topic but all my N-frame 629's have flame cutting. My 69 does as well but is minor and has not been shot a lot. I shoot only 240 grain XTP over a full charge of H110.

The oldest and highest round count 629 has flame cutting that progressed to a point then has gone no further with many years and many thousands of rounds subsequently.

Just my personal experience. The only revolvers that I worry about flame cutting are alloy frame with a missing blast shield or a blast shield that is cut through.

 

[garbler]

Flame cutting or erosion is not particular to just revolvers but has been studied and talked about with rifle barrels back during Hatcher's time and Parker Ackley. It wasn't top strap or forcing cones but chamber throats eroding or burning out and ruining accuracy. It was the opinion of many that throat erosion was attributable to slower powders and over-bore barrel cartridge combos where unburned powder is the side effect along with powder kernels hitting and eroding the barrel. Ackley puts it this way in his book Handbook For Shooters And Reloaders

" that the sand blasting effect of the unburned portion of slow burning powders being blown
out into the barrel at terrific velocity would have an even more marked effect than extreme
heat alone "

The revolver with its cylinder chambers and throats, cylinder gap and forcing cone barrel entry offer even more avenues for hot gases and unburned powder to erode internal and nearby metal surfaces. Unlike most rifles the revolver with hotter loads pretty much falls into the category of being over-bore. It's pretty much impossible to get highest velocity in handgun length barrels without using slower powders, roughly from Blue Dot on. In so doing you almost always find unburned powder on the bench out front but this condition can be greatly improved with good bullets properly sized, hard cast and the right powder. Faster powders and heavier longer bullets will quickly push you into the pressure red zone if you're not careful. So it appears handguns really can't burn all the slower powders fed them. Years ago I saw a demo where a 357 S&W and a Blackhawk with full power 2400 and H110 loads were shot in a cardboard box. There was burn spots and unburned powder both sides of the cylinder.


With severe flame cutting you get erosion or impingement attack of the forcing cone and leading edges of the barrel shank and the top strap in worst case scenarios. Slower burning powders are jetted out of the chamber in a column of hot gas and progressively burning powder kernels. The ignited powder hits the cylinder gap and if open to the atmosphere the pressure and unburned powder kernels do what pressure does, it looks for an escape route. The closest surfaces to erode or impinge would be the leading edges of the forcing cone and the top strap in line with the cylinder gap. The two areas showing the most aggressive erosion.

Above when I said if cylinder gap is open, well that I believe is a key. Quite a few years ago there was some testing and research following the discovery that some loads generated more pressure in revolvers than pistols and other guns. Hard to believe given there is a cylinder gap to bleed off pressure ? But this is what was discovered

Ignition first then as the base of the bullet clears the mouth of the case the pressure upsets the base of the bullet to form a seal in the chamber mouth while the front band of the bullet engages the forcing cone and bore. With the base sealing the chamber and nose engaged and being swaged down before the bullet can clear the cylinder the gap is sealed, and all of this is happening at generally peak pressure with most pistol powders. Of course bullet design and forcing cone length and angle will have a lot to do with this but nevertheless its a pressure condition that will create a lot of stress on the gun. I'm not saying it will blow a gun up but certainly batter it. With most faster pistol powders peak pressure is generated within the cylinder meaning most if not all the powder is consumed. Not so with the slower magnum powders.

As I see it longer heavier bullets properly sized, shot in a gun with proper throating and forcing cone, and a cylinder and yoke running true should reduce the chances for serious flame and powder erosion. Veral Smith ( LBT ) has always said the deeper a bullet is seated the less powder needed resulting in generally higher velocity for given powder charge, less noise and generally superior accuracy. The smaller powder charge moving a heavier bullet results in more pressure and a more complete burn since the bullet remains in the throat and barrel longer giving the powder time to generate maximum energy. The longer heavier bullet not only provides a greater bearing surface to rifling for stability and accuracy but will span and seal off the cylinder gap for a longer period insuring a better powder burn and less flame and unburned kernels being jetted into the leading edge of the cone and top strap.

Exceptions to a degree would be shorter powder columns, perhaps hotter primers and certainly heavier crimps all of which generally promote complete ignition. It is usually the magnum cartridges with longer powder columns that develop lots of flame and erosion issues. The 357 Max is a perfect example.

Lighter shorter bullets being pushed with slower powders will leave the cylinder gap open longer as the bullet makes the jump to the cone faster as the slower powder burns. The lighter bullet out front creates a longer time interval for hot gas and unburned powder to be jetted out and escape thru the gap hitting the top strap and leading edges of the cone. The lighter bullets move ahead of the progressively burning slower powders resulting in less pressure, more unburned propellant and generally less accuracy compared to heavier longer bullets. Heavier crimps can help here to a degree but a primer alone will break a crimp and push a bullet into the bore. In fact lighter bullets are probably pushed well ahead of the burning powder column when magnum primers are used. This too probably results in quantities of unburned powder kernels forced out of the gap.

The longer bullets however, on a properly gapped gun, will span the gap jump and create a bit more pressure allowing for a better/longer burn and less kernel blasting or impingement. It seems to me very light short bullets and slower powder can create the right physical conditions that result in this erosion problem. And worse would be shooting these lighter shorter jacketed bullets if measured smaller than groove diameter. The jacketed bullet will not obturate or upset to groove diameter so now your loosing pressure, full burn and accuracy with lots more hot gas and powder causing problems. All of the above assumes the cylinder gap is reasonable and the yoke and cylinder are true. In other words a properly set up and functioning gun. Anyway that is how I see it.

Rick

 

[colt_saa]

Just because something is the weakest point, why do people automatically assume that it means the item is too weak for the job

If the initial part was designed by the engineers to be 3 times stronger than necessary (parts are alwasy dsigned to be stronger then necessary) and that scoring took away a hypothetical 10% of the strength, then the part still remains 2.7 times stronger than necessary

Listen to the engineers that designed the product when they tell you not to worry. Those engineers are not relying on plain old Common Sense, they are relying on years of Engineering School

If the danger was something other than just in our minds, Smith & Wesson would recall the item just like they recalled the L-frames with the bushing issue and just like they recalled the 3" 329s for the frame cracking issue

There is no conspiracy to save Smith & Wesson money replacing frames. If there was a real danger, Smith & Wesson would put the lives of their Customers first just as they have always done during the last 163 years of being in business

 

[Pisgah]

I've said it before, I'll say it again -- I have been messing with revolvers for almost 60 years and have never seen a single case of a revolver failing by flame-cutting. If you have one, show it -- but I don't believe anyone can. Until someone does, I am going with -- flame cutting? Not a problem.

 

[hkcavalier]

If it was a real structural issue, manufacturers would have something there to deal with it. I know in some of the alloy frames there's that steel insert.

Does Korth have a tungsten or rhodium insert, replacement part $399?

 

[sonora]

What about shooting 125 Gr jacketed bullets with non +P ammo? Over time will this flame cut the top strap over time?

 

[garbler]

Seems many here feel the flame cutting issues with the top strap don't cross the line to structural compromise. Understand that but looks like nobody is acknowledging the damage to the forcing cone and barrel shank ( review photos in other thread ). The erosion and damage here will most certainly cost you accuracy and finally a barrel or at least a barrel set back to correct. Either way much more costly than superficial top strap damage. Where you find top strap cutting you always find worse damage to the forcing cone and barrel shank edges.

Rick

 

[stansdds]

What about shooting 125 Gr jacketed bullets with non +P ammo? Over time will this flame cut the top strap over time?

Although there may still be some cutting, I don't think it would be anywhere near the degree that occurs with full power 110 and 125 grain 357 Magnum loads. You also will not see the same degree of erosion at the edge of the barrel's forcing cone.

 

[moosedog]

Ah yes the old flame cutting debut. For you doubters here's an extreme example. After just 100 rounds of 125gr JHP 357's. Warranty wouldn't cover it.

 

[Protocall_Design]

Ah yes the old flame cutting debut. For you doubters here's an extreme example. After just 100 rounds of 125gr JHP 357's. Warranty wouldn't cover it.

Bad case of flame cutting for sure...

 

[Pisgah]

I well recall back before some of you were born when flame cutting first made headlines in the gun rags. In 1983 Ruger had released the Blackhawk in the new .357 Maximum cartridge, and reviewers began noting a NEW, NEVER BEFORE SEEN phenomenon -- flame cutting of the frame above the barrel-cylinder gap. Note again, this was big news because it was not commonly seen in lesser cartridges. Ruger eventually withdrew the .357 Max from the market, but even they stated that the cutting did NOT represent any danger to the shooter or to the structural integrity of the guns -- it was just that PUBLIC PERCEPTION, although quite incorrect, was negative about it. Since then the phenomenon of flame cutting, which was never common or dangerous, has become both in the public view -- which is still wrong.

 

[Puritan]

I thought the original other post was pretty silly. Load up a hot load that is flame cutting your revolver and then ask what you should do about it. To me it is like stating that every time you hit your thumb with a sledge hammer it hurts and then asking what you should do about it.

I didn't think that post was silly at all, but then again I wrote it. I was asking the expert gunsmiths on the forum for recommendations on how to stop flame cutting from getting worse while developing a hot light load for possible future use. Sure, the problem can be solved by only shooting heavier bullets or reduced power loads, but that wasn't the goal. I think a more accurate analogy would be choosing to stay indoors during the summertime for fear of getting sun burned instead of applying sunscreen. I just need to find the right sunscreen.

 

[Protocall_Design]

The right sunscreen is heavier bullets (158 gr. and up) and non-ball powder. You can make some pretty heavy magnum loads that way.