Top Strap Flame Cutting Fix Recommendations

Puritan · Jul 11, 2020

Recently I began developing a max velocity 125 gr load for my 23 year old model 686-4 357 magnum revolver and sure enough the dreaded top strap flame cutting started to develop with some forcing cone erosion as well. I've read varying opinions ranging from not to worry about the flame cutting because it stops eventually before rendering the revolver dangerous, to stop using the revolver immediately if you value your life. From what I can tell, the depth of the cut is only about 1/16" at the deepest part so I'm confident the firearm is still safe to use, but I was hoping to do something to prevent the flame cutting from getting worse. How would a gunsmith address this issue?

I saw online that someone placed a piece of spring steel above the forcing cone on a S&W revolver, but there were no details on the type of spring steel or where to get a piece that fits neatly without much fitting. My initial thought was to apply some stainless steel tape in that area, but I'm pretty sure that would only be a temporary solution with me having to replace the tape frequently. Would something like JB Weld be useful in filling in the groove and preventing further cutting? I'm hoping to get recommendations from the experts on the forum for something that I can do at home with my limited machining skills and tools.

Below is a picture of the revolver and a closeup picture of the top strap and forcing cone.

I don't normally shoot full power 125 gr magnum loads, but I wanted to have some Thanks in advance.

mscampbell2734 · Jul 11, 2020

OK I'll have a go. How many current manufactures use some sort of shield on their steel framed revolvers to stop/prevent flame cutting? ZERO

There's a reason ZERO manufactures feel the need to reinforce/shield that area.

Now if you just got to have something done then in fact S&W on some of their alloy framed magnums did use a steel shield.

Like this.

revolver flame cutting shield - Google Search

Good luck on finding a smith willing to install something similar.

bigggbbruce · Jul 11, 2020

Puritan said:
Recently I began developing a max velocity 125 gr load for my 23 year old model 686-4

I don't normally shoot full power 125 gr magnum loads, but I wanted to have some Thanks in advance.

The best fix by far would be to stop shooting them. You see what they do to your gun.

Peak53 · Jul 11, 2020

Shoot flame throwers, expect flames.

I'm curious as to what load has produced this result. There may be other options.

ggibson511960 · Jul 11, 2020

Nasty!

That's pretty severe flame cutting. It's not the depth of the cut I would worry about, but the stress riser that it creates. If this happened after a low round count, it's time to stop using this load and find another way. I'm sure the piece is safe, but it's time to change course. One of the pictures in the search link showed a neat piece of carefully cut sheet metal formed into the hot zone. This could work great as a sacrificial shield, but I would be wary of it flying off in bad directions if not carefully secured by careful bending. The sight screw hold might offer a securing point. It's interesting to note that the front sight screw has not been ablated like the surrounding frame material.

BC38 · Jul 11, 2020

I take the Grandpa Jones approach.
It flame cuts my revolver when I shoot those...
...WELL THEN DON'T SHOOT THOSE!

Seriously though, I don't shoot hot light loads in my 357's - specifically to avoid flame cutting and forcing cone erosion issues.

Injunbro · Jul 11, 2020

I don't think your gun is dangerous but will become that way if you keep it up. Forget the JB weld, it's plastic glue, not a fire shield. Then stop using those flamethrower loads, 158 grain semi jacketed semi wadcutters have been used on everything from grizzly's on down. Anything bigger than that needs a cannon.

steelslaver · Jul 12, 2020

When I was youngerr everything was a max load.

Duh, if it is going to be dead at 1000fps why do I need 1300fps.
A lot of 50 self defense or hunting lots maybe and thats a week maybe. Sight it tto the load and go do it

But face it 99.9 percent of what we do with our guns is paper, plinking and practice and I fail to see where 300fps makes that much difference in those endeavors. Why abuse your gun for nothing.

Fishinfool · Jul 12, 2020

When I started with the CSP, our issue load was the Remington .357 magnum 125 grain SJHP load, and it was a hot one. Spent a lot of my off time at the SP range, and so it was available for my use for free. That said, I put maybe 1000 rounds of it thru my duty 586, along with a couple thousand full power 158 grain mag reloads, and many thousands of .38 spl PPC loads, as this was also my PPC gun. Total flame cutting maybe a little more than yours. Self limiting. I have never seen a revolver become unsafe to shoot because of flame cutting shooting safe and sane loads. But, I guess any mechanical device can be worn to ruin given enough use.

My Ruger Redhawk (my hot load test mule) has thousands of hot .44 mag loads thru it, and again, flame cutting reaches a certain point, them stops. I will note that I have read that ball powders tend to be more abrasive in hot loads, but have not seen any conclusive proof. My favorite magnum powder is Win-296, which happens to be a ball powder.

Work up a good, hot 125 grain load, load a couple hundred for future use, then concentrate on milder, heavier bullet loads for 99% of your normal shooting, and your gun will be fine.

Larry

Lou_the_welder · Jul 12, 2020

I did wreck the force cone out of my 627 and it did end up having some flame cutting. One of the last pics I had that showed some wear, but not when it finally got bashed in with the cylinder on a speed load.

On my 627, right around 11k rounds did I finally turn it back in to the factory. They fixed the force cone and left it looking good as new. Warranty repair.
The consensus on flame cutting has always been that it cuts to a certain point and no more.

ddixie884 · Jul 12, 2020

Didn't I read somewhere that a layer of pencil lead will help with flame cutting.............

steveno · Jul 12, 2020

first of all that is far from being .062 deep. get out your calipers and dial up .062 on it and compare.

after a certain point the flame cutting will stop because the depth will be deeper that the focus point of the gas coming through the cylinder gap.

a 357 doesn't need a LOT of velocity to be effective. a 140 grain bullet is a good minimum for the 357. leave the 125 grain bullets for the 38 special.

if you insist on using the 125 grain bullets at high velocity change powders

by the way any high pressure revolver round will have this problem

to add a little more on flame cutting when Ruger came out with the 357 max everybody complained about the cutting it turned out they the cutting came from the fact they were using the 125 grain bullets with heavy charges of H-110/WW-296. it wasn't near the problem once you went to 158 grain and heavier bullets and used a powder like 4227. the cutting was still there but reached a point where it was no longer an issue or a safety issue. for those of you that have a Ruger 357 max revolver do NOT send it back to Ruger as they will keep it and you will not get it back

chief38 · Jul 12, 2020

I have not shot 125 grain Magnums out of my Revolvers for 30 years because of this. The 125 grainers are known to be the culprit. I only shoot 158 grain Magnums. While the velocity is slower - the foot pounds of energy is more than enough to get the job done! That said, I shoot less Magnums and more .38 Specials when it comes to punching holes in paper.... no need to beat myself, the gun or my ears up anymore than they already are. Just a few per year for familiarization with my "Bear Load" - Buffalo Bore 180 Grain hard cast LSCW 357 Mag.

s&wchad · Jul 12, 2020

It’s perfectly safe to shoot that gun. I’d limit the use of light bullet magnum loads in the future, but I wouldn’t be concerned about that minor cutting.

AlHunt · Jul 12, 2020

The forcing cone damage would concern me more. It's going to continue, regardless. I can't think of any good reason to do that to a recreational gun. The barrel can always be re-cut and set back for a cost, of course, so it's not the end of the world.

stansdds · Jul 12, 2020

ddixie884 said:
Didn't I read somewhere that a layer of pencil lead will help with flame cutting.............

I have read that too, not sure if it works, I stopped shooting those flame thrower loads.

Pisgah · Jul 12, 2020

A couple of observations on flame-cutting:

1. It's not all that common. Yes, it exists, but if you look closely you will find on most revolvers that what you are seeing is usually just a build-up of firing debris , or at most an etched line, and not a "cut". It is a characteristic wear pattern resulting from the way a revolver works, and it does no harm.

2. It's not a problem. Think about it -- in all the talk of flame cutting have you ever seen a single report of a revolver failing because of it? Neither have I. It has zero effect on the safety or accuracy of a revolver.

Now, forcing cone erosion is a different proposition in that it can over time seriously affect accuracy. But again, it is a normal wear pattern for a revolver.

garbler · Jul 12, 2020

Nobody has mentioned this yet but as I recall back in the old 357 Max scare days a number of knowledgeable observers attributed cone erosion and flame cutting to certain powders. You don’t say whether these are full power factory loads or your own or what powder. I’m a bit fuzzy on this but I seem to recall ball powders like H110 etc were the worst offenders but I could be wrong. The argument went like this. Normally ball powders don’t burn any hotter but burn progressively or a bit slower due to their deterrent coating. Due to this burn rate characteristic the powder is still burning hot and not completely consumed ( some balls still intact ) into gas between the cylinder throats and barrel. Not a big problem in a pistol but a revolver with cylinder gap is different. Just spitballing here but the forcing cone should be cleaned up if accuracy is important.

Rick

2152hq · Jul 12, 2020

One thing I notice is that OP's revolver bbl only has flame cutting to the edge & face of the bbl itself at the 12 oclock position,,and that seems to have cut into the top strap right above it.

No other portion of the circumference of the barrel face is effected by any of the same type of damage.

Unlike Post #10, Lou the Welder's 357 where the entire bbl face shows the same type damage s I would expect it to.

I realize that Lou's may have a much higher round count and thus more damage to it.
But I'd still expect the OP's gun to show what damage we do see at the 12oclock position not only there,,but evenly all around the breech face of the bbl.

Could the bbl face be 'off' square with an extra wide gap at the top,,or even the face of the cylinder not be square with the bbl face?

That these revolvers do 'gas cut' is not a question. I only wonder why this one shows the issue at the 12oclock position only.

I agree that the depth of the cutting so far is very much less than the estimate given. The revolver is still safe for use IMO.

I never liked hyper magnum loads either,,in any firearm.
Excess wear and strain to get few extra fps wow factor.

Narragansett · Jul 12, 2020

I guess that i would shoot the intended 158gr bullet as a standard. To me, it is not worth shooting out a gun for a few more FPS. I have seen people shoot 90 gr. .355 9mm bullets to get some zip. Just me, but i do not see the point

Top Strap Flame Cutting Fix Recommendations

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