Flame cutting questions

[guitar1580]

Could someone educate me a little on this subject? I know that it's the condition of escaping gasses burning a groove in the top strap, but at what point does one become concerned?

One person told me that it will only burn so far, and then stop. I've seen a 1917 which had been shot alot and has a substantial groove.

Does it weaken the frame at some point, and how does one know when it is getting too bad?

Thx, Josh P

 

[pownal55]

You don't really have to worry about it. After many thousands of magnum loads it looks like a hack saw cut but never seems to get deep enough to damage the gun. the use of slow burning ball powders like HII0 and W296 will accelerate the problem.

 

[palmetto99]

My "beater" model 19-4 has flame cutting on the top strap. It's an ex-leo gun ans has seen a fair amount of use. It's still pretty solid and shoots very well.

 

[n4zov]

Flame cutting is one of those topics that just will not go away and it comes up on the forum at least once a month. It causes a lot of concern, but I have never seen the slightest evidence that it is a real problem that could cause structural failure of the gun. It is just cosmetic as far as I know.

 

[Oscar Zulu]

The 1917 has a fairly large divot milled into the topstrap. I think this was left over from the black powder era and has more to do with fouling than flame cutting. Hit it with a wire brush and I think you will find it uniform and fairly wide. Flame cutting does look like a hacksaw cut.
OZ

 

[Snapping Twig]

Typically it goes only so far and then stabilizes.

More of an issue when ball powder is used with light (short) bullets in magnum cartridges.

Forcing cone condition plays a role here as well, but to a lesser degree.

I used H110 ball powder under 110 and 125 grain JHP's in a 586 and it had a fair amount of flame cutting but not enough to degrade performance.

Using a heavier (long) bullet allows the powder additional time to burn more completely and therefore not have particles sandblasting the top strap.

In a non magnum round like the .45acp, generally there's not much to worry about.

Keep it clean and watch it and I'm convinced that over time it will not grow.

 

[guitar1580]

Oz, I believe you nailed it dead on! Upon closer inspection with a magnifying glass & flashlight, I can see that the indentation is milled into the strap, oval or football shaped with clean symmetrical edges.

Thx for all the help, you guys are great!

Josh P

 

[handejector]

Great photo.
Yes, that is the fouling cup.
In the pic, you can actually see MINUTE flame cutting at the forward edge of the cup. It may only be carbon, but that is what it will look like.

 

[Oscar Zulu]

Ha, Ha! I thought I had the same issues with mine. I am just passing on what I learned right here. These guys and gals are a great pool of knowledge! Good luck.
OZ

 

[guitar1580]

Fouling Cup !! There's the word we're looking for to add to our vocabulary, thx Lee.

Josh P