Powders That Generate a Lot of Heat

[superbee922]

I was just reading the fairly recent thread about Lil Gun powder. A poster expressed concern about the use of this powder possibly damaging revolvers. I have seen this concern expressed elsewhere.

Would somebody be able to explain to me why this particular powder generates so much heat and flame? Are there some other powders which behave in a similar manner when used in revolver / pistols reloads?

Also, approximately how many rounds (approximately, of course) loaded with Lil Gun would need to be fired through a revolver before said damage to backstrap and forcing cone occurred?

 

[jim8115]

I do know this. I have a new GP100 that has to have the barrell replaced due to extreme flame cutting / erosion. I am not sure which loads are responsible.
We shoot mostly 38's, and light unique 357 loads from it. But, we have shot several hundred 125 grain XTP's wih a full charge of H-110 , and 158 cast with Lil gun.
Whichever load did it, it didnt take many.


JIM

 

[788Ham]

There is another thread, I believe in the "revolver" section, mentioning the use of 125 gr. bullets, used in a model #19 Smith. The use of 125 gr. bullets caused the erosions/splitting of the forcing cone on that particular revolver, maybe this is why your revolver has gone South! The use of H110 powder might have attributed to the demise also? Might check the thread out.

 

[788Ham]

On this same page, scroll down to a thread titled, "Lil gun power", they'll attest to what I said earlier.

 

[rodregier]

I've read that light jacketed projectiles and large charges of H110/W296 have been implicated in accelerated flame cutting. Apparently especially notorious in .357 Maximum with revolvers.

 

[rcmodel]

to explain to me why this particular powder generates so much heat and flame?

I am of the opinion that 'flame cutting' is a misnomer.

What I believe happens with slow burning ball powder is, unburned powder is blasted out of the B/C gap, and acts just like sandblasting beads to cut the top strap.

There is no possible way a flame can heat a solid piece of steel hot enough to melt or cut it in the brief milli-second the blast is there.

It takes even a acetylene cutting torch a few seconds to heat steel hot enough to melt & cut it.

And there is no evidence Lil Gun powder erodes rifles barrels any faster, or at all, then then any other powder.

rc

 

[PO2Hammer]

I think Lilgun has a high nitroglycerin content with a lot of deterrents to slow down the burn. The high nitroglycerin content creates the heat and the deterrents keep the pressure from going off the charts. Instead of a quick kick in the bullet's but like most pistol powders would give, it's more of a blow torch effect.
I dunno, just my guess.

 

[kingmt]

Ever seen a plasma cutter? Held slightly of the surface it will blast a hole as soon as it hits it. Hold it against the surface where the air can't blow by & it will barely make a mark.

 

[brickeyee]

I am of the opinion that 'flame cutting' is a misnomer.

You are correct.

Closer to plasma cutting.

 

[gamestalker]

Closer to a plasma cutter indeed. The hot, high pressure gases are what actually does the cutting. They skirt through the cylinder gap in a knife like manner, very knife like, considering the gap on most wheel guns is between .004" and .008", and then they simply cut into the strap.
But the good news is, there is no way they will ever cut completely through, even with H110 and other extremely slow burning ball powders. Most strap cutting damage will stall at about .010" or so.
Now as for forcing cone damage, this is a case of those same super heated high pressure gases blowing past a shorter profile bullet, and striking the forcing cone. This is most evident with light projectiles, such 125 gr and 110 gr..
GS

 

[Cosmoline]

In my experience the hottest powder by far is black, which will heat a revolver up far faster than any smokeless. But the heat is not the problem unless you're dealing with full auto and actual buildup of enough energy to start melting things.

 

[kingmt]

I have watched YouTubes of revolvers coming apart at the backstrap. I also know a buddy that his BP came apart. Seems like something to worry about to me.

 

[BullfrogKen]

Black powder definitely heats a gun up.

Titegroup runs pretty hot as well.

 

[Vacek]

What made cordite so erosive. Not abrasion as it was extruded string. I thought that some powders slowly eroded by heat, so I may be learning something different here.

 

[Bovice]

Titegroup is hot. That's why I don't use it. But it's regarded as being fast, so what are we blaming for flame cutting? Is it heat from fast powder or slow powder with a longer lasting burn?

 

[ljnowell]

Here is my take on powders that burn hot. I load my 38 special wadcutters for Bullseye league with AA#2. When I practice rapid fire its not uncommon to go through a 50 rd box in a matter of 10 minutes.

My uncle was reloading with W231, and a friend of ours in our league uses Titegroup. These are the ONLY two guys that I would ever share reloads with, or for that matter, shoot their reloads. One day we were talking about this same topic so we decided to do some tested. We each took 12 of the others loads. We then each shot two cylinders of one ammo, felt the gun and used an infrared thermo. Then we let it cool. Did that for all three. Its been a while so I cant say the exact numbers, but the 231 was a noticable bit hotter than the AA#2 and the Titegroup was MUCH hotter than the other two. Like way hotter.

It was interesting to say the least. I am also proud to announce that my loads were the most accurate for everyone that day too, lol.

 

[Comrade Mike]

Looks like I wont be burning up any more titegroup once Im done with the two pounds I have. Move on to experiment with other things.

 

[GaryL]

There is no possible way a flame can heat a solid piece of steel hot enough to melt or cut it in the brief milli-second the blast is there.

It takes even a acetylene cutting torch a few seconds to heat steel hot enough to melt & cut it.

Flame cutting may not be the correct term, but there can be some strange stuff taking place when you have a flow of hot gas. It doesn't have to melt the metal to abraid the surface. I've seen some strange physics in various things I've done on the job. Plasma etching of surfaces doesn't require any real heating of the material. That uses a high voltage electron flow, which can also happen in a moving gas (not unlike storm clouds).

Femto second lasers are like a special class of plasma cutters. The short burst of light is enough to rip apart atoms by stripping away electrons, and a flowing gas carries them away. There is no heat affect zone in the material being cut. So I think it's possible to have something similar take place with a jet of flame. The laser process isn't fast; it would take a bit more than a few seconds to cut a trench like you would see in the top strap of a 357 mag pistol.

But I suspect you are correct about material blasting as well. Sometimes there are several things working together to cause an effect.

Anyway, this isn't a call out, just simply pointing out there are many ways to cut metal. Some of them are weird science.

 

[kwg020]

Just my thought but slower powder burns longer and has the opportunity to pass more heat to the metal. A fast powder would be hot close to the ignition source but fade away the further it gets away from the source. That is probably why black powder gets guns so hot, it burns longer, all the way to the end of the barrel.. I agree wth rcmodel, it will never get hot enough to cut or melt metal but it may erode it over time. JMHO kwg

 

[Comrade Mike]

You guys are starting to scare me now. What powders should I avoid if I don't want to flame cut the back strap off my new model 10?

 

[Peter M. Eick]

PO2hammer hit the point. It is the nitroglycerin content. Just avoid the high nitro powders and you should be fine avoiding heat.

If you want to avoid the sand blast effect, avoid ball powders in revolvers.

It is really pretty simple. I don't put any ball powders in high pressure type revolvers anymore. Only use flake or stick powders and you are fine. Low pressure like 38 special or 45 colt, go ahead and use ball powders, it is not a big deal. Things like the 357 Maximum, only stick powders like 4227.

Pretty much you can assume any dense ball powder has the potential of causing grief in a revolver. So avoid things like Lilgun, titegroup, h110 or 296, aa9/aa7 etc. The issue is though these same powders give some great performance so like most things, "there is no such thing as a free lunch".

 

[788Ham]

Comrade,

For a light load for your .38, load 4.0 gr. of Win 231 under 158 gr. SWC, about 750 - 800 fps, like I said, a light load. Good for target practice, no leading of the barrel, cleans up easily!

 

[ArchAngelCD]

Comrade,

For a light load for your .38, load 4.0 gr. of Win 231 under 158 gr. SWC, about 750 - 800 fps, like I said, a light load. Good for target practice, no leading of the barrel, cleans up easily!

That is my favorite .38 Special load by far, 4.0gr W231 under a 158gr LSWC...